Frew, Adam - Mycorrhizal Ecology

@article{huang_contrasting_2026,
	title = {Contrasting strategies of two \textit{{Camellia} oleifera} cultivars in shaping arbuscular mycorrhizal fungi communities under different phosphorus forms},
	volume = {128},
	issn = {1164-5563},
	url = {https://www.sciencedirect.com/science/article/pii/S1164556326000129},
	doi = {10.1016/j.ejsobi.2026.103814},
	abstract = {Phosphorus (P) availability regulates the arbuscular mycorrhizal fungi (AMF) symbiosis, but the distinct effects of different P forms (soluble, insoluble, organic) and host plant genotypes on AMF communities remain underexplored. Using Camellia oleifera cultivars with contrasting P-use efficiencies (low-P-sensitive CL3 and low-P-tolerant CL40), we examined how P forms and cultivar identity shape AMF communities and their functional linkages to plant growth and soil nutrients. The results showed that soluble inorganic P (SP) maximized plant height and biomass but suppressed AMF diversity and simplified co-occurrence networks. In contrast, insoluble inorganic P (IP) enhanced AMF colonization rates and stabilized microbial interactions. The low-P-sensitive CL3 hosted a higher Chao1 index under P limitation, suggesting compensatory recruitment for P acquisition, while CL40 exhibited stronger soil P activation and maintained complex AMF networks. Glomus and Paraglomus were identified as core taxa in the rhizosphere AMF networks of C. oleifera. RDA and Mantel analyses showed that variation in plant growth and root traits was aligned with AMF characteristics, particularly colonization and core taxa (Glomus, Paraglomus), and strongly associated with soil nutrients, with SP treatment reducing mycorrhizal dependence and shifting associations toward Paraglomus. These insights inform targeted cultivar selection and phosphorus management to optimize C. oleifera production and maintain soil health.},
	urldate = {2026-03-17},
	journal = {European Journal of Soil Biology},
	author = {Huang, Yuxuan and You, Xin and Frew, Adam and Wu, Fei and Zhang, Linping and Liu, Xinping and Xing, Jiaoping},
	month = mar,
	year = {2026},
	keywords = {Arbuscular mycorrhizal fungi diversity, Cultivar, Phosphorus forms, Rhizosphere},
	pages = {103814},
}

Phosphorus (P) availability regulates the arbuscular mycorrhizal fungi (AMF) symbiosis, but the distinct effects of different P forms (soluble, insoluble, organic) and host plant genotypes on AMF communities remain underexplored. Using Camellia oleifera cultivars with contrasting P-use efficiencies (low-P-sensitive CL3 and low-P-tolerant CL40), we examined how P forms and cultivar identity shape AMF communities and their functional linkages to plant growth and soil nutrients. The results showed that soluble inorganic P (SP) maximized plant height and biomass but suppressed AMF diversity and simplified co-occurrence networks. In contrast, insoluble inorganic P (IP) enhanced AMF colonization rates and stabilized microbial interactions. The low-P-sensitive CL3 hosted a higher Chao1 index under P limitation, suggesting compensatory recruitment for P acquisition, while CL40 exhibited stronger soil P activation and maintained complex AMF networks. Glomus and Paraglomus were identified as core taxa in the rhizosphere AMF networks of C. oleifera. RDA and Mantel analyses showed that variation in plant growth and root traits was aligned with AMF characteristics, particularly colonization and core taxa (Glomus, Paraglomus), and strongly associated with soil nutrients, with SP treatment reducing mycorrhizal dependence and shifting associations toward Paraglomus. These insights inform targeted cultivar selection and phosphorus management to optimize C. oleifera production and maintain soil health.

@article{kasige_interactions_2026,
	title = {Interactions between beneficial fungi and plant silicon: {A} review},
	volume = {114},
	copyright = {© 2025 The Author(s). Journal of Ecology © 2025 British Ecological Society.},
	issn = {1365-2745},
	shorttitle = {Interactions between beneficial fungi and plant silicon},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/1365-2745.70207},
	doi = {10.1111/1365-2745.70207},
	abstract = {Silicon (Si) accumulation in plants often plays an important functional role by alleviating the adverse impacts of the plant antagonists (e.g. invertebrate herbivores). Mutualistic associations with beneficial fungi, such as below-ground arbuscular mycorrhizal (AM) fungi and above-ground Epichloë endophytes, play similar roles for plant protection. Evidence suggests that beneficial fungi significantly influence Si uptake, often increasing Si in plant tissues while Si supplementation may in turn enhance fungal colonisation. However, this two-way association remains poorly understood due to the fragmented nature of existing literature. We assess the current state of knowledge on interactions between Si and beneficial fungi by extracting and comparing effect sizes (Cohen's d) from peer-reviewed literature for various reported relationships. We aim to understand the (i) interactions between Si and beneficial fungi, (ii) potential mechanisms underlying their interactions and (iii) role of Si-fungal interactions in enhancing plant resilience to environmental stresses. The Glomeraceae AM family was the most frequently investigated and was generally associated with increased Si accumulation in plants (overall effect size, d = 0.7). Additionally, Si supplementation was commonly reported to have a positive effect, with a modest overall increase in AM fungal colonisation (overall effect size, d = 0.3). These observations are often associated with changes in plant growth, morphology, physiology and chemistry by either Si or fungi. The literature covering Epichloë endophytes was limited and showed highly variable, strain-specific trends. Interactions between Si supply and beneficial fungi have mostly been studied in the context of abiotic stresses with limited focus on biotic antagonists (only nine studies). However, the extent to which Si and beneficial fungi increased plant resistance to stresses suggests that their interactions could play a significant role in plant community dynamics, potentially disadvantaging plant species that lack these traits. Synthesis. This review aims to help predict how beneficial fungi may interact with Si supply to enhance resistance to environmental stresses. Overall, Si supply and beneficial fungi seem to work ‘synergistically’ especially when Si availability is low, or when the plant species is a low Si accumulator. Finally, we identified potential avenues for future research based on existing knowledge and key knowledge gaps.},
	language = {en},
	number = {1},
	urldate = {2026-03-17},
	journal = {Journal of Ecology},
	author = {Kasige, Ramalka Heshani and Cibils-Stewart, Ximena and Frew, Adam and Johnson, Scott Nicholas},
	year = {2026},
	note = {\_eprint: https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2745.70207},
	keywords = {Epichloë endophytes, arbuscular mycorrhizal fungi, silica, silicon accumulation, silicon uptake},
	pages = {e70207},
}

Silicon (Si) accumulation in plants often plays an important functional role by alleviating the adverse impacts of the plant antagonists (e.g. invertebrate herbivores). Mutualistic associations with beneficial fungi, such as below-ground arbuscular mycorrhizal (AM) fungi and above-ground Epichloë endophytes, play similar roles for plant protection. Evidence suggests that beneficial fungi significantly influence Si uptake, often increasing Si in plant tissues while Si supplementation may in turn enhance fungal colonisation. However, this two-way association remains poorly understood due to the fragmented nature of existing literature. We assess the current state of knowledge on interactions between Si and beneficial fungi by extracting and comparing effect sizes (Cohen's d) from peer-reviewed literature for various reported relationships. We aim to understand the (i) interactions between Si and beneficial fungi, (ii) potential mechanisms underlying their interactions and (iii) role of Si-fungal interactions in enhancing plant resilience to environmental stresses. The Glomeraceae AM family was the most frequently investigated and was generally associated with increased Si accumulation in plants (overall effect size, d = 0.7). Additionally, Si supplementation was commonly reported to have a positive effect, with a modest overall increase in AM fungal colonisation (overall effect size, d = 0.3). These observations are often associated with changes in plant growth, morphology, physiology and chemistry by either Si or fungi. The literature covering Epichloë endophytes was limited and showed highly variable, strain-specific trends. Interactions between Si supply and beneficial fungi have mostly been studied in the context of abiotic stresses with limited focus on biotic antagonists (only nine studies). However, the extent to which Si and beneficial fungi increased plant resistance to stresses suggests that their interactions could play a significant role in plant community dynamics, potentially disadvantaging plant species that lack these traits. Synthesis. This review aims to help predict how beneficial fungi may interact with Si supply to enhance resistance to environmental stresses. Overall, Si supply and beneficial fungi seem to work ‘synergistically’ especially when Si availability is low, or when the plant species is a low Si accumulator. Finally, we identified potential avenues for future research based on existing knowledge and key knowledge gaps.

@article{frew_ausamf_2025,
	title = {{AusAMF}: {The} {Database} of {Arbuscular} {Mycorrhizal} {Fungal} {Communities} in {Australia}},
	volume = {34},
	copyright = {© 2025 The Author(s). Global Ecology and Biogeography published by John Wiley \& Sons Ltd.},
	issn = {1466-8238},
	shorttitle = {{AusAMF}},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/geb.70090},
	doi = {10.1111/geb.70090},
	abstract = {Motivation Arbuscular mycorrhizal (AM) fungi are central to plant nutrient acquisition, soil carbon dynamics, and ecosystem resilience. Yet, their biogeography remains incompletely characterised, particularly across underrepresented regions. Australia, with its characteristic ecological conditions, continental scale, and long-standing evolutionary trajectories, has been notably undersampled. This gap hinders our ability to make comprehensive inferences about AM fungal diversity, community composition, and ecological roles at global scales. The AusAMF database was created to address this deficiency by compiling high-throughput AM fungal community data across mainland Australia and Tasmania. The initial release comprises data from 610 georeferenced sites sampled between 2011 and 2023, covering all major climate zones and accompanied by standardised soil storage, DNA extraction, and sequencing procedures. Developed through a nationally coordinated effort, AusAMF offers a rare level of methodological consistency, enabling robust spatial and temporal comparisons while minimising post-sampling technical biases. Its design as a purpose-built, extensible platform ensures continued expansion using harmonised protocols—something not achieved through compiled datasets assembled retrospectively from disparate studies. Each sample is linked to associated environmental variables, allowing users to explore ecological drivers of AM fungal distributions, assess patterns of biodiversity, and support applications spanning from fundamental ecology to conservation planning. As such, AusAMF advances both regional and global efforts to characterise the diversity and ecological significance of these foundational plant symbionts. Main Types of Variables Contained Georeferenced occurrence and abundance of high-throughput amplicon sequences of arbuscular mycorrhizal fungi. Spatial Location and Grain Australia. Decimal degrees between 0.0001 and 0.1 resolution. Time Period and Grain 2011–2023. Month and year of sampling. Major Taxa and Level of Measurement Arbuscular mycorrhizal fungi identified to family, genus, and virtual taxon (VT). Geographic occurrence and amplicon sequence abundance. Software Format Interact with processed data via online application (https://www.ausamf.com). Dataset available as .csv files and raw sequencing data as .fastq files.},
	language = {en},
	number = {7},
	urldate = {2026-03-17},
	journal = {Global Ecology and Biogeography},
	author = {Frew, Adam and Powell, Jeff R. and Heuck, Meike K. and Albornoz, Felipe E. and Birnbaum, Christina and Dearnaley, John D. W. and Egidi, Eleonora and Finn, Luke and Kath, Jarrod and Koorem, Kadri and Oja, Jane and Öpik, Maarja and Vahter, Tanel and Vasar, Martti and Watts-Williams, Stephanie and Zheng, Yuxiong and Aguilar-Trigueros, Carlos A.},
	year = {2025},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/geb.70090},
	keywords = {Australia, DNA metabarcoding, arbuscular mycorrhizal fungi, high-throughput sequencing, plant symbionts, soil fungi, symbiosis},
	pages = {e70090},
}

Motivation Arbuscular mycorrhizal (AM) fungi are central to plant nutrient acquisition, soil carbon dynamics, and ecosystem resilience. Yet, their biogeography remains incompletely characterised, particularly across underrepresented regions. Australia, with its characteristic ecological conditions, continental scale, and long-standing evolutionary trajectories, has been notably undersampled. This gap hinders our ability to make comprehensive inferences about AM fungal diversity, community composition, and ecological roles at global scales. The AusAMF database was created to address this deficiency by compiling high-throughput AM fungal community data across mainland Australia and Tasmania. The initial release comprises data from 610 georeferenced sites sampled between 2011 and 2023, covering all major climate zones and accompanied by standardised soil storage, DNA extraction, and sequencing procedures. Developed through a nationally coordinated effort, AusAMF offers a rare level of methodological consistency, enabling robust spatial and temporal comparisons while minimising post-sampling technical biases. Its design as a purpose-built, extensible platform ensures continued expansion using harmonised protocols—something not achieved through compiled datasets assembled retrospectively from disparate studies. Each sample is linked to associated environmental variables, allowing users to explore ecological drivers of AM fungal distributions, assess patterns of biodiversity, and support applications spanning from fundamental ecology to conservation planning. As such, AusAMF advances both regional and global efforts to characterise the diversity and ecological significance of these foundational plant symbionts. Main Types of Variables Contained Georeferenced occurrence and abundance of high-throughput amplicon sequences of arbuscular mycorrhizal fungi. Spatial Location and Grain Australia. Decimal degrees between 0.0001 and 0.1 resolution. Time Period and Grain 2011–2023. Month and year of sampling. Major Taxa and Level of Measurement Arbuscular mycorrhizal fungi identified to family, genus, and virtual taxon (VT). Geographic occurrence and amplicon sequence abundance. Software Format Interact with processed data via online application (https://www.ausamf.com). Dataset available as .csv files and raw sequencing data as .fastq files.

@article{frew_causal_2025,
	title = {Causal determinism by plant host identity in arbuscular mycorrhizal fungal community assembly},
	volume = {39},
	issn = {1365-2435},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/1365-2435.14715},
	doi = {10.1111/1365-2435.14715},
	abstract = {An assumption in ecology is that plant identity plays a central role in the assembly of root-colonising arbuscular mycorrhizal (AM) fungal communities. While numerous correlational studies support this notion, with evidence of host selectivity among fungal taxa and host-specific responses to different AM fungi, empirical demonstrations of host-driven AM fungal community assembly remain surprisingly limited. We conducted a factorial experiment growing two globally significant crop species, wheat (Triticum aestivum) and sorghum (Sorghum bicolor), with a common pool of AM fungal species, or without AM fungi. We hypothesised strong differences in AM fungal community structure between the two species driven by strong habitat filtering. Plants were harvested at two time points in which we analysed the community structure of AM fungi in the roots, the phylogenetic diversity, and interactions with plant physiological responses. As we expected, there were distinct trajectories in both the composition and phylogenetic diversity of AM fungal communities between the two host plants through time. However, the effect of habitat filtering during community assembly differed between the two species. In sorghum roots, AM fungal communities exhibited increased richness and became more phylogenetically clustered over time. This shift suggests that community assembly was primarily driven by habitat filtering, or selectivity, imposed by the host which was accompanied by significant increases in plant mycorrhizal growth (from 11.83\% to 43.67\%) and phosphorus responses (from −0.6\% to 43.3\%). In contrast, AM fungal communities in wheat displayed little change in diversity, remained phylogenetically unstructured, and provided minimal benefits to the host, indicating a more stochastic assembly process with a stronger influence of competitive interactions. As the field looks to understand what determines the distribution of AM fungi and their community composition while simultaneously seeking to utilise AM fungi for ecosystem benefits, it is important to know the extent to which host identity can influence fungal assembly within plant roots. Our results provide empirical support of host-determinism in AM fungal community assembly and suggest that this determinism is associated with the growth and nutrient benefits provided by the symbiosis to plants. Read the free Plain Language Summary for this article on the Journal blog.},
	language = {en},
	number = {2},
	urldate = {2026-03-17},
	journal = {Functional Ecology},
	author = {Frew, Adam and Zheng, Yuxiong and Wang, Zhenyu and Fu, Yanrong and Aguilar-Trigueros, Carlos A.},
	year = {2025},
	note = {\_eprint: https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2435.14715},
	keywords = {arbuscular mycorrhiza, environmental filtering, fungal community, host selection, plant roots, symbiosis},
	pages = {390--402},
}

An assumption in ecology is that plant identity plays a central role in the assembly of root-colonising arbuscular mycorrhizal (AM) fungal communities. While numerous correlational studies support this notion, with evidence of host selectivity among fungal taxa and host-specific responses to different AM fungi, empirical demonstrations of host-driven AM fungal community assembly remain surprisingly limited. We conducted a factorial experiment growing two globally significant crop species, wheat (Triticum aestivum) and sorghum (Sorghum bicolor), with a common pool of AM fungal species, or without AM fungi. We hypothesised strong differences in AM fungal community structure between the two species driven by strong habitat filtering. Plants were harvested at two time points in which we analysed the community structure of AM fungi in the roots, the phylogenetic diversity, and interactions with plant physiological responses. As we expected, there were distinct trajectories in both the composition and phylogenetic diversity of AM fungal communities between the two host plants through time. However, the effect of habitat filtering during community assembly differed between the two species. In sorghum roots, AM fungal communities exhibited increased richness and became more phylogenetically clustered over time. This shift suggests that community assembly was primarily driven by habitat filtering, or selectivity, imposed by the host which was accompanied by significant increases in plant mycorrhizal growth (from 11.83% to 43.67%) and phosphorus responses (from −0.6% to 43.3%). In contrast, AM fungal communities in wheat displayed little change in diversity, remained phylogenetically unstructured, and provided minimal benefits to the host, indicating a more stochastic assembly process with a stronger influence of competitive interactions. As the field looks to understand what determines the distribution of AM fungi and their community composition while simultaneously seeking to utilise AM fungi for ecosystem benefits, it is important to know the extent to which host identity can influence fungal assembly within plant roots. Our results provide empirical support of host-determinism in AM fungal community assembly and suggest that this determinism is associated with the growth and nutrient benefits provided by the symbiosis to plants. Read the free Plain Language Summary for this article on the Journal blog.

@article{aguilar-trigueros_connecting_2025,
	title = {Connecting the dots: {Network} structure as a functional trait in arbuscular mycorrhizal fungi},
	issn = {2572-2611},
	shorttitle = {Connecting the dots},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/ppp3.70058},
	doi = {10.1002/ppp3.70058},
	abstract = {Societal Impact Statement Soil health and sustainable land management are critical to addressing global challenges such as food security, climate resilience, and biodiversity loss. Arbuscular mycorrhizal (AM) fungi form underground networks that enhance plant nutrient uptake and improve soil structure, yet their functional diversity remains poorly understood, limiting their application in agriculture and ecosystem restoration. By proposing potential fungal transport strategies, we provide a framework for predicting AM fungal contributions across different environments. This knowledge can inform agricultural practices, conservation strategies, and land-use policies, ultimately supporting efforts to harness beneficial microbes for resilient and sustainable ecosystems. Summary Arbuscular mycorrhizal (AM) fungi construct extensive mycelial networks in soil, serving as critical mediators of plant–soil interactions and nutrient exchange. However, the ability to harness AM fungal diversity for ecosystem management remains constrained by gaps in functional understanding. Trait-based frameworks offer a promising approach to overcoming these limitations, yet their development has been hindered by methodological challenges and the complexity of AM fungal symbioses. Here, we propose that mycelial network connectivity, a structural trait reflecting the organization of fungal hyphae for nutrient transport, provides a mechanistic basis for distinguishing AM fungal functional groups. Drawing on network theory, we identify two key trade-offs that shape AM fungal transport strategies: (1) a trade-off between transport efficiency and resilience to structural disruption and (2) a positive correlation between network heterogeneity and soil heterogeneity. Based on these relationships, we classify AM fungi into potential functional groups and argue that these connectivity-based classifications provide a predictive framework for understanding AM fungal ecological strategies across environmental gradients, with implications for sustainable land management. Future research should integrate experimental measurements of fungal carbon allocation, network plasticity, and species-specific responses to environmental change to refine this framework further. By linking mycelial architecture to functional diversity, this approach enhances our ability to predict AM fungal contributions to ecosystem processes and optimize their use in applied contexts.},
	language = {en},
	urldate = {2026-03-17},
	journal = {PLANTS, PEOPLE, PLANET},
	author = {Aguilar-Trigueros, Carlos A. and Frew, Adam},
	month = jun,
	year = {2025},
	note = {\_eprint: https://nph.onlinelibrary.wiley.com/doi/pdf/10.1002/ppp3.70058},
	pages = {1--10},
}

Societal Impact Statement Soil health and sustainable land management are critical to addressing global challenges such as food security, climate resilience, and biodiversity loss. Arbuscular mycorrhizal (AM) fungi form underground networks that enhance plant nutrient uptake and improve soil structure, yet their functional diversity remains poorly understood, limiting their application in agriculture and ecosystem restoration. By proposing potential fungal transport strategies, we provide a framework for predicting AM fungal contributions across different environments. This knowledge can inform agricultural practices, conservation strategies, and land-use policies, ultimately supporting efforts to harness beneficial microbes for resilient and sustainable ecosystems. Summary Arbuscular mycorrhizal (AM) fungi construct extensive mycelial networks in soil, serving as critical mediators of plant–soil interactions and nutrient exchange. However, the ability to harness AM fungal diversity for ecosystem management remains constrained by gaps in functional understanding. Trait-based frameworks offer a promising approach to overcoming these limitations, yet their development has been hindered by methodological challenges and the complexity of AM fungal symbioses. Here, we propose that mycelial network connectivity, a structural trait reflecting the organization of fungal hyphae for nutrient transport, provides a mechanistic basis for distinguishing AM fungal functional groups. Drawing on network theory, we identify two key trade-offs that shape AM fungal transport strategies: (1) a trade-off between transport efficiency and resilience to structural disruption and (2) a positive correlation between network heterogeneity and soil heterogeneity. Based on these relationships, we classify AM fungi into potential functional groups and argue that these connectivity-based classifications provide a predictive framework for understanding AM fungal ecological strategies across environmental gradients, with implications for sustainable land management. Future research should integrate experimental measurements of fungal carbon allocation, network plasticity, and species-specific responses to environmental change to refine this framework further. By linking mycelial architecture to functional diversity, this approach enhances our ability to predict AM fungal contributions to ecosystem processes and optimize their use in applied contexts.

@article{jiao_contrasting_2025,
	title = {Contrasting effects of above and belowground litter inputs in shaping the soil microbiome worldwide},
	volume = {515},
	issn = {1573-5036},
	url = {https://doi.org/10.1007/s11104-025-07591-4},
	doi = {10.1007/s11104-025-07591-4},
	abstract = {Microbes are the primary decomposers of litter, yet how above and belowground litter inputs contribute to soil microbial structure and function remains unclear across global environmental gradients.},
	language = {en},
	number = {1},
	urldate = {2026-03-17},
	journal = {Plant and Soil},
	author = {Jiao, Hongzhe and Delgado-Baquerizo, Manuel and Frew, Adam and Li, Weiwei and Zhai, Kaiyan and Yu, Qingshui and Zhou, Guiyao},
	month = oct,
	year = {2025},
	keywords = {Litter input, Meta-analysis, Microbial biomass, SOM decomposition, Soil microbiome},
	pages = {363--375},
}

Microbes are the primary decomposers of litter, yet how above and belowground litter inputs contribute to soil microbial structure and function remains unclear across global environmental gradients.

@inproceedings{maerowitz-mcmahan_ashes_2025,
	title = {From {Ashes} to {Insights}: {Mycorrhizal} {Fungi} {Functions} in {Post}-{Fire} {Landscapes}},
	shorttitle = {From {Ashes} to {Insights}},
	url = {https://ui.adsabs.harvard.edu/abs/2025EGUGA..2715087M},
	doi = {10.5194/egusphere-egu25-15087},
	abstract = {Communities in fire-affected ecosystems possess unique traits that aid survival and ecosystem recovery post-fire. As fires increase in frequency and intensity due to climate change, we enter a time increasingly influenced by fire therefore understanding the functions of these communities in forested systems is essential. While previous work has been done on the presence or absence of mycorrhizal fungi post-fire, generally using DNA-based approaches, there is limited knowledge about the functions they serve. This work aimed to identify functional traits of mycorrhizal fungi that correlate with fire regime and vegetative composition.Thirty dry sclerophyll forest sites surrounding the Sydney basin that burned in the 2019-2020 black summer fires of Australia were selected based on historical gradients in fire severity and interval. Vegetative composition, fungal communities as well as soil carbon and nutrient availability were analysed from each site, from these, a subset of sites were selected for further study to distinguish direct (via effects on fire regimes) and indirect (via effects on nutrient availability) on mycorrhizal fungal functional traits associated with biomass production, hyphal chemistry (carbon, nitrogen, and phosphorus concentrations). For this, we harvested mycorrhizal fungal biomass using mesh in-growth bags filled with plastic resin-beads that absorb mineralized nutrients.Available nutrients influenced mycorrhizal fungal community structure and biomass production in material collected from in-growth bags, whereas fire regime and vegetative structure had no effect. Hyphal chemistry was not significantly associated with nutrient availability, vegetative structure, or fire regime. In contrast, soil-derived data revealed significant effects of fire frequency on community structure, but no influence of nutrient availability or vegetative structure.By integrating responses related to functional traits, fungal community composition, vegetation structure, and environmental factors, we aim to understand not only the functions that individual fungi provide in forested systems but also how these communities function collectively. We highlight the contrasting effects of fire frequency and nutrient availability on mycorrhizal communities in soil compared to those collected with mesh in-growth bags. These differences in community structure across sites likely reflect fungal growth strategies and their sensitivity to nutrient availability.},
	urldate = {2026-03-17},
	author = {Maerowitz-McMahan, Solomon and Frew, Adam and Gordon, Chris and Nolan, Rachael and Powell, Jeff},
	month = apr,
	year = {2025},
	note = {ADS Bibcode: 2025EGUGA..2715087M},
	pages = {EGU25--15087},
}

Communities in fire-affected ecosystems possess unique traits that aid survival and ecosystem recovery post-fire. As fires increase in frequency and intensity due to climate change, we enter a time increasingly influenced by fire therefore understanding the functions of these communities in forested systems is essential. While previous work has been done on the presence or absence of mycorrhizal fungi post-fire, generally using DNA-based approaches, there is limited knowledge about the functions they serve. This work aimed to identify functional traits of mycorrhizal fungi that correlate with fire regime and vegetative composition.Thirty dry sclerophyll forest sites surrounding the Sydney basin that burned in the 2019-2020 black summer fires of Australia were selected based on historical gradients in fire severity and interval. Vegetative composition, fungal communities as well as soil carbon and nutrient availability were analysed from each site, from these, a subset of sites were selected for further study to distinguish direct (via effects on fire regimes) and indirect (via effects on nutrient availability) on mycorrhizal fungal functional traits associated with biomass production, hyphal chemistry (carbon, nitrogen, and phosphorus concentrations). For this, we harvested mycorrhizal fungal biomass using mesh in-growth bags filled with plastic resin-beads that absorb mineralized nutrients.Available nutrients influenced mycorrhizal fungal community structure and biomass production in material collected from in-growth bags, whereas fire regime and vegetative structure had no effect. Hyphal chemistry was not significantly associated with nutrient availability, vegetative structure, or fire regime. In contrast, soil-derived data revealed significant effects of fire frequency on community structure, but no influence of nutrient availability or vegetative structure.By integrating responses related to functional traits, fungal community composition, vegetation structure, and environmental factors, we aim to understand not only the functions that individual fungi provide in forested systems but also how these communities function collectively. We highlight the contrasting effects of fire frequency and nutrient availability on mycorrhizal communities in soil compared to those collected with mesh in-growth bags. These differences in community structure across sites likely reflect fungal growth strategies and their sensitivity to nutrient availability.

@article{xiao_microplastics_2025,
	title = {Microplastics aggravate zinc deficiency-induced inhibition of physiological-biochemical characteristics in apple rootstock \textit{{Malus} hupehensis} ({Pamp}.) {Rehd} seedlings},
	volume = {11},
	issn = {2405-6650},
	url = {https://www.sciencedirect.com/science/article/pii/S2405665024001227},
	doi = {10.1016/j.emcon.2024.100421},
	abstract = {Both microplastic (MP) pollution and zinc (Zn) deficiency have adverse effects on terrestrial plants. However, the combined effect of MPs and Zn deficiency on plant physiology remains unexplored. In this study, a pot-culture experiment and 13C stable isotope tracing technology were employed to investigate the combined effects of MPs and Zn deficiency on the growth, photosynthetic physiology and chlorophyll fluorescence characteristics, as well as synthesis and distribution of photosynthetic products in Malus hupehensis (Pamp.) Rehd seedlings. The results revealed significant reductions in biomass, gas exchange parameters, carbohydrate metabolism enzyme activities, and photosynthetic parameters including Fv/Fm, ΦPSII, ETR and qp in seedlings subjected to both individual and joint treatments of MPs and Zn deficiency compared to the control group. Notably, the combined Zn deficiency and MPs exhibited a more pronounced inhibitory effect on root biomass (RR = −0.42) compared to the single Zn deficiency (RR = −0.37) and MP (RR = −0.26) treatments. Random forest analysis indicated that chlorophyll fluorescence characteristics (37.5 \%) had the greatest impact on biomass variation in seedlings, followed by 13C accumulation in various organs (26.7 \%). MPs exacerbated the inhibition of photosynthesis (Pn and Gs) under Zn deficiency by suppressing chlorophyll fluorescence parameters (Fv/Fm and ΦPSII), further reducing 13C accumulation in roots. In conclusion, the addition of MPs intensified the suppression of photosynthetic parameters caused by Zn deficiency, weakened the carbon assimilation capacity of leaves, and hindered the synthesis of photosynthetic products in leaves and their transport to roots, thereby further inhibiting root growth. This study reveals the combined stress of MP pollution and Zn deficiency on terrestrial plants, deepens our understanding of potential ecological risks, and provides scientific basis for the development of effective mitigation measures to protect plant ecosystems.},
	number = {1},
	urldate = {2026-03-17},
	journal = {Emerging Contaminants},
	author = {Xiao, Haoyan and Yu, Hanxia and Frew, Adam and Jiang, Wei and Wu, Yusen and Wang, Cheng and Xi, Beidou and Tan, Wenbing},
	month = mar,
	year = {2025},
	keywords = {(Pamp.) Rehd, C photosynthate accumulation, Combined effect, Microplastics, Photosynthesis, Zinc deficiency},
	pages = {100421},
}

Both microplastic (MP) pollution and zinc (Zn) deficiency have adverse effects on terrestrial plants. However, the combined effect of MPs and Zn deficiency on plant physiology remains unexplored. In this study, a pot-culture experiment and 13C stable isotope tracing technology were employed to investigate the combined effects of MPs and Zn deficiency on the growth, photosynthetic physiology and chlorophyll fluorescence characteristics, as well as synthesis and distribution of photosynthetic products in Malus hupehensis (Pamp.) Rehd seedlings. The results revealed significant reductions in biomass, gas exchange parameters, carbohydrate metabolism enzyme activities, and photosynthetic parameters including Fv/Fm, ΦPSII, ETR and qp in seedlings subjected to both individual and joint treatments of MPs and Zn deficiency compared to the control group. Notably, the combined Zn deficiency and MPs exhibited a more pronounced inhibitory effect on root biomass (RR = −0.42) compared to the single Zn deficiency (RR = −0.37) and MP (RR = −0.26) treatments. Random forest analysis indicated that chlorophyll fluorescence characteristics (37.5 %) had the greatest impact on biomass variation in seedlings, followed by 13C accumulation in various organs (26.7 %). MPs exacerbated the inhibition of photosynthesis (Pn and Gs) under Zn deficiency by suppressing chlorophyll fluorescence parameters (Fv/Fm and ΦPSII), further reducing 13C accumulation in roots. In conclusion, the addition of MPs intensified the suppression of photosynthetic parameters caused by Zn deficiency, weakened the carbon assimilation capacity of leaves, and hindered the synthesis of photosynthetic products in leaves and their transport to roots, thereby further inhibiting root growth. This study reveals the combined stress of MP pollution and Zn deficiency on terrestrial plants, deepens our understanding of potential ecological risks, and provides scientific basis for the development of effective mitigation measures to protect plant ecosystems.

@article{liu_mycorrhizae-associated_2025,
	title = {Mycorrhizae-associated belowground economics mediate microbial life history strategy in temperate forests},
	volume = {463},
	issn = {0016-7061},
	url = {https://www.sciencedirect.com/science/article/pii/S001670612500415X},
	doi = {10.1016/j.geoderma.2025.117574},
	abstract = {The co-evolution of plant roots, mycorrhizal fungi, and soil saprotrophic microorganisms shapes underground resource acquisition strategies of plants. However, the knowledge of how mycorrhizal associations affect plant belowground economics strategy and rhizosphere microbial community is not well established. Here we sampled leaves, roots and rhizosphere soils from five arbuscular mycorrhizal (AM) and seven ectomycorrhizal (EcM) tree species in a mixed temperate forest to explore the impacts of mycorrhizal associations on plant above- and belowground functional traits and rhizosphere microbial community composition. Mycorrhizal associations regulate soil fungal community composition, root functional traits, and economics space, but do not impact leaf traits. AM trees adopt a more aggressive strategy for nutrient acquirement with higher specific root length and root nitrogen concentration and support greater abundance of fungal community with nutrient acquirement strategy compared to EcM trees. The mycorrhizal-associated belowground economics spectrum, which ranges from conservative to aggressive nutrient acquisition strategies, was positively correlated with the relative abundance of the aggressive-strategy saprotrophic fungi (Ascomycota), while the conservative-strategy fungi (Rozellomycota) were associated with the opposite end of the spectrum. Our study highlights the importance of the mycorrhizal-associated belowground economics spectrum in mediating microbial functional groups and ecological strategies. Integrating mycorrhizal-mediated interactions into root economics framework could improve predictions of nutrient cycling and ecosystem functioning in temperate forests.},
	urldate = {2026-03-17},
	journal = {Geoderma},
	author = {Liu, Ruiqiang and Du, Wenya and Frew, Adam and He, Yanghui and Guo, Liqi and Yan, Xiaolei and Zhou, Guiyao and Zhai, Kaiyan and Xiang, Guangzhen and Zhu, Yimin and Zhou, Xuhui},
	month = nov,
	year = {2025},
	keywords = {Microbial strategy, Mycorrhizal type, Root economics, Root traits, Soil nutrient cycles},
	pages = {117574},
}

The co-evolution of plant roots, mycorrhizal fungi, and soil saprotrophic microorganisms shapes underground resource acquisition strategies of plants. However, the knowledge of how mycorrhizal associations affect plant belowground economics strategy and rhizosphere microbial community is not well established. Here we sampled leaves, roots and rhizosphere soils from five arbuscular mycorrhizal (AM) and seven ectomycorrhizal (EcM) tree species in a mixed temperate forest to explore the impacts of mycorrhizal associations on plant above- and belowground functional traits and rhizosphere microbial community composition. Mycorrhizal associations regulate soil fungal community composition, root functional traits, and economics space, but do not impact leaf traits. AM trees adopt a more aggressive strategy for nutrient acquirement with higher specific root length and root nitrogen concentration and support greater abundance of fungal community with nutrient acquirement strategy compared to EcM trees. The mycorrhizal-associated belowground economics spectrum, which ranges from conservative to aggressive nutrient acquisition strategies, was positively correlated with the relative abundance of the aggressive-strategy saprotrophic fungi (Ascomycota), while the conservative-strategy fungi (Rozellomycota) were associated with the opposite end of the spectrum. Our study highlights the importance of the mycorrhizal-associated belowground economics spectrum in mediating microbial functional groups and ecological strategies. Integrating mycorrhizal-mediated interactions into root economics framework could improve predictions of nutrient cycling and ecosystem functioning in temperate forests.

@article{frew_mycorrhizal_2025,
	title = {Mycorrhizal networks: {Understanding} hidden complexity},
	volume = {39},
	copyright = {© 2025 The Author(s). Functional Ecology published by John Wiley \& Sons Ltd on behalf of British Ecological Society.},
	issn = {1365-2435},
	shorttitle = {Mycorrhizal networks},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/1365-2435.70063},
	doi = {10.1111/1365-2435.70063},
	abstract = {The symbiotic relationship between mycorrhizal fungi and plants predates the origin of roots and has played a key role in shaping ecosystems for hundreds of millions of years. In associating with multiple plants simultaneously, mycorrhizal fungi can form complex below-ground networks that directly—and indirectly—influence plant communities, plant and soil resource dynamics, and broader ecosystem processes. Research has provided increasing insight into the structure and function of these networks, including the movement and exchange of resources between symbionts, the mechanisms governing fungal and plant community assembly, and their potential applications in land management. As public interest in mycorrhizal networks has grown, so too have calls within the scientific community for greater clarity regarding their ecological functionality and broader significance. This Special Focus brings together research that advances our understanding of these networks from multiple perspectives. Contributions explore the hierarchical complexity of fungal-plant associations, the ecological and functional implications of mycorrhizal selectivity, the resource exchange dynamics, and their relevance in applied contexts, such as agriculture. By synthesising emerging evidence, this collection highlights key advances while also identifying unresolved questions and the future research directions necessary for disentangling the ecological roles of mycorrhizal networks. Read the free Plain Language Summary for this article on the Journal blog.},
	language = {en},
	number = {6},
	urldate = {2026-03-17},
	journal = {Functional Ecology},
	author = {Frew, Adam and Varga, Sandra and Klein, Tamir},
	year = {2025},
	note = {\_eprint: https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2435.70063},
	keywords = {below-ground networks, community assembly, mycorrhizal fungi, mycorrhizal selectivity, plant communities, resource exchange},
	pages = {1322--1327},
}

The symbiotic relationship between mycorrhizal fungi and plants predates the origin of roots and has played a key role in shaping ecosystems for hundreds of millions of years. In associating with multiple plants simultaneously, mycorrhizal fungi can form complex below-ground networks that directly—and indirectly—influence plant communities, plant and soil resource dynamics, and broader ecosystem processes. Research has provided increasing insight into the structure and function of these networks, including the movement and exchange of resources between symbionts, the mechanisms governing fungal and plant community assembly, and their potential applications in land management. As public interest in mycorrhizal networks has grown, so too have calls within the scientific community for greater clarity regarding their ecological functionality and broader significance. This Special Focus brings together research that advances our understanding of these networks from multiple perspectives. Contributions explore the hierarchical complexity of fungal-plant associations, the ecological and functional implications of mycorrhizal selectivity, the resource exchange dynamics, and their relevance in applied contexts, such as agriculture. By synthesising emerging evidence, this collection highlights key advances while also identifying unresolved questions and the future research directions necessary for disentangling the ecological roles of mycorrhizal networks. Read the free Plain Language Summary for this article on the Journal blog.

@article{heuck_organic_2025,
	title = {Organic management shapes {AM} fungal community structure and function, partially mitigating the negative effects of conventional agriculture},
	volume = {39},
	copyright = {© 2024 The Author(s). Functional Ecology published by John Wiley \& Sons Ltd on behalf of British Ecological Society.},
	issn = {1365-2435},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/1365-2435.14732},
	doi = {10.1111/1365-2435.14732},
	abstract = {Arbuscular mycorrhizal (AM) fungi are important plant symbionts that provide plants with nutrients and water as well as support plant defences against pests and disease. Consequently, they present a promising alternative to using environmentally damaging and costly fertilisers and pesticides in agricultural systems. However, our limited understanding of how agricultural practices impact AM fungal diversity and functions is a key impediment to using them effectively in agriculture. We assessed how organic and conventional agricultural management systems shaped AM fungal communities. We also investigated how AM fungal communities derived from these agricultural management systems affected crop biomass and development. Six soil samples from five organically and five conventionally managed agricultural sites were used to cultivate Sorghum bicolor. Plant growth, plant nutrient concentrations and AM fungal colonisation rates were analysed alongside DNA metabarcoding of community composition. We observed that soil from conventional agricultural fields resulted in a pronounced reduction in sorghum biomass (−53.6\%) and a significant delay in flowering compared to plants grown without AM fungi. Sorghum biomass was also reduced with soil from the organic system, but to a lesser extent (−30\%) and without a delay in flowering. Organic systems were associated with a large proportion of AM fungal taxa (50.5\% of VTs) not found in conventional systems, including Diversispora (r2 = 0.09, p {\textless} 0.001), Archaeospora (r2 = 0.07, p {\textless} 0.001) and Glomus (r2 = 0.25, p {\textless} 0.001) spp., but also shared a large proportion of taxa with conventional systems (42.3\% of VTs). Conventional systems had relatively few unique taxa (7.2\% of VTs). Our results suggest that conventional agricultural practices selected against AM fungi that were, in this context, more beneficial for host plants. In contrast, organic management practices mitigate this negative effect, likely due to the presence of specific key AM fungal taxa. However, this mitigation is only partial, as less beneficial AM fungal taxa still persist, probably due to abiotic factors associated with agricultural management and the sensitivity of AM fungi to these factors. This persistence explains why the effect is not entirely eradicated. Read the free Plain Language Summary for this article on the Journal blog.},
	language = {en},
	number = {6},
	urldate = {2026-03-17},
	journal = {Functional Ecology},
	author = {Heuck, Meike Katharina and Powell, Jeff R. and Kath, Jarrod and Birnbaum, Christina and Frew, Adam},
	year = {2025},
	note = {\_eprint: https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2435.14732},
	keywords = {arbuscular mycorrhizal fungi, biological soil fertility, community composition, food security, sustainable agriculture},
	pages = {1328--1342},
}

Arbuscular mycorrhizal (AM) fungi are important plant symbionts that provide plants with nutrients and water as well as support plant defences against pests and disease. Consequently, they present a promising alternative to using environmentally damaging and costly fertilisers and pesticides in agricultural systems. However, our limited understanding of how agricultural practices impact AM fungal diversity and functions is a key impediment to using them effectively in agriculture. We assessed how organic and conventional agricultural management systems shaped AM fungal communities. We also investigated how AM fungal communities derived from these agricultural management systems affected crop biomass and development. Six soil samples from five organically and five conventionally managed agricultural sites were used to cultivate Sorghum bicolor. Plant growth, plant nutrient concentrations and AM fungal colonisation rates were analysed alongside DNA metabarcoding of community composition. We observed that soil from conventional agricultural fields resulted in a pronounced reduction in sorghum biomass (−53.6%) and a significant delay in flowering compared to plants grown without AM fungi. Sorghum biomass was also reduced with soil from the organic system, but to a lesser extent (−30%) and without a delay in flowering. Organic systems were associated with a large proportion of AM fungal taxa (50.5% of VTs) not found in conventional systems, including Diversispora (r2 = 0.09, p \textless 0.001), Archaeospora (r2 = 0.07, p \textless 0.001) and Glomus (r2 = 0.25, p \textless 0.001) spp., but also shared a large proportion of taxa with conventional systems (42.3% of VTs). Conventional systems had relatively few unique taxa (7.2% of VTs). Our results suggest that conventional agricultural practices selected against AM fungi that were, in this context, more beneficial for host plants. In contrast, organic management practices mitigate this negative effect, likely due to the presence of specific key AM fungal taxa. However, this mitigation is only partial, as less beneficial AM fungal taxa still persist, probably due to abiotic factors associated with agricultural management and the sensitivity of AM fungi to these factors. This persistence explains why the effect is not entirely eradicated. Read the free Plain Language Summary for this article on the Journal blog.

@inproceedings{heuck_seasonality_2025,
	title = {Seasonality drives arbuscular mycorrhizal ({AM}) fungal community responses while future climate alters {AM} fungi-mediated phosphorus uptake in plant functional groups},
	url = {https://ui.adsabs.harvard.edu/abs/2025EGUGA..2710089H},
	doi = {10.5194/egusphere-egu25-10089},
	abstract = {Arbuscular mycorrhizal (AM) fungi form symbiosis with most terrestrial plants, facilitating nutrient and water uptake while contributing to ecosystem services such as nutrient cycling, soil carbon sequestration, and plant resilience to abiotic stressors. As such, these fungi hold significant potential in advancing climate-change-resilient agriculture. However, their effectiveness in supporting agricultural resilience depends on their own responses to global change, which remain poorly understood due to species-specific and context-dependent variability across agricultural systems and climate scenarios.To address this knowledge gap, we investigated AM fungal community responses at the Global Change Experimental Facility (GCEF) in Bad Lauchstädt, Germany. Established in 2014, the experiment consists of 5 blocks assigned to ambient climate and 5 to a future climate scenario, simulating the expected climate in Central Germany for 2070-2100, based on the consensus of several climate models. The future climate scenario simulates changes in temperature and precipitation patterns. Within each block, we focused on two distinct land-use types, extensive mowing or grazing, typically used for supporting livestock production. The meadows were mown or grazed one to three times annually, depending on plant biomass production. AM fungal community data from 160 soil samples, collected across eight time points spanning two years (mid-2020 to mid-2022) and differentiated by the two land-use types, were analysed using DNA metabarcoding. Additionally, plant biomass and nutrient concentrations were assessed.Hierarchical Modelling of Species Communities (HMSC) revealed that, across land-use types and climate scenarios, seasonality was the dominant driver of AM fungal variance in the abundance and occurrence model. Plant growing season spring was the primary influence on AM fungal responses, particularly regarding alpha indices and phylogeny. In addition, Glomeraceae abundance increased in spring (p: 0.043), potentially highlighting its role in providing fast nutrient supply for host plants. However, future climate scenarios dampened these seasonal patterns, particularly in mowed systems, suggesting a shift in the dynamics of AM symbiosis. Additionally, we observed plant functional group-specific effects: under future climate, phosphorus uptake by grasses (p: 0.11) and forbs (p: 0.027) correlated with AM fungal phylogenetic clustering, while legumes exhibited an opposite pattern, with phosphorus uptake correlating with phylogenetic dispersion (p: 0.021). We speculate that this might be due to the dual symbiosis of legumes with AM fungi and nitrogen-fixing bacteria. Thus, these findings contribute to providing insight into the functional roles of AM fungal communities under future climate and suggest that considering plant functional group composition may become more critical for managing these systems in the future.},
	urldate = {2026-03-17},
	author = {Heuck, Meike Katharina and Reitz, Thomas and Rioscher, Christiane and Powell, Jeff R. and Birnbaum, Christina and Kath, Jarrod and Philipp, Lena and Stoltenburg, Regina and Hoffmann, Petra and Harpole, W. Stanley and Frew, Adam},
	month = apr,
	year = {2025},
	note = {ADS Bibcode: 2025EGUGA..2710089H},
	pages = {EGU25--10089},
}

Arbuscular mycorrhizal (AM) fungi form symbiosis with most terrestrial plants, facilitating nutrient and water uptake while contributing to ecosystem services such as nutrient cycling, soil carbon sequestration, and plant resilience to abiotic stressors. As such, these fungi hold significant potential in advancing climate-change-resilient agriculture. However, their effectiveness in supporting agricultural resilience depends on their own responses to global change, which remain poorly understood due to species-specific and context-dependent variability across agricultural systems and climate scenarios.To address this knowledge gap, we investigated AM fungal community responses at the Global Change Experimental Facility (GCEF) in Bad Lauchstädt, Germany. Established in 2014, the experiment consists of 5 blocks assigned to ambient climate and 5 to a future climate scenario, simulating the expected climate in Central Germany for 2070-2100, based on the consensus of several climate models. The future climate scenario simulates changes in temperature and precipitation patterns. Within each block, we focused on two distinct land-use types, extensive mowing or grazing, typically used for supporting livestock production. The meadows were mown or grazed one to three times annually, depending on plant biomass production. AM fungal community data from 160 soil samples, collected across eight time points spanning two years (mid-2020 to mid-2022) and differentiated by the two land-use types, were analysed using DNA metabarcoding. Additionally, plant biomass and nutrient concentrations were assessed.Hierarchical Modelling of Species Communities (HMSC) revealed that, across land-use types and climate scenarios, seasonality was the dominant driver of AM fungal variance in the abundance and occurrence model. Plant growing season spring was the primary influence on AM fungal responses, particularly regarding alpha indices and phylogeny. In addition, Glomeraceae abundance increased in spring (p: 0.043), potentially highlighting its role in providing fast nutrient supply for host plants. However, future climate scenarios dampened these seasonal patterns, particularly in mowed systems, suggesting a shift in the dynamics of AM symbiosis. Additionally, we observed plant functional group-specific effects: under future climate, phosphorus uptake by grasses (p: 0.11) and forbs (p: 0.027) correlated with AM fungal phylogenetic clustering, while legumes exhibited an opposite pattern, with phosphorus uptake correlating with phylogenetic dispersion (p: 0.021). We speculate that this might be due to the dual symbiosis of legumes with AM fungi and nitrogen-fixing bacteria. Thus, these findings contribute to providing insight into the functional roles of AM fungal communities under future climate and suggest that considering plant functional group composition may become more critical for managing these systems in the future.

@article{zheng_stand_2025,
	title = {Stand ages and soil compartments jointly shape ecosystem multifunctionality via changes in bacterial and fungal diversity and community composition},
	volume = {514},
	issn = {1573-5036},
	url = {https://doi.org/10.1007/s11104-025-07566-5},
	doi = {10.1007/s11104-025-07566-5},
	abstract = {Soil microbes play critical roles in supporting multiple ecosystem functions in forests. Their community characteristics are strongly influenced by the soil compartments they occupy (e.g., rhizosphere and bulk soils) as well as stand ages during plantation restoration. However, little is known about whether the effects of microbial communities on soil multifunctionality differ between soil compartments and how these effects are influenced by stand stages.},
	language = {en},
	number = {2},
	urldate = {2026-03-17},
	journal = {Plant and Soil},
	author = {Zheng, Yuxiong and Frew, Adam and Egidi, Eleonora and Yang, Zhijie and Lin, Chengfang},
	month = sep,
	year = {2025},
	keywords = {Microbial diversity, Plantation forests, Rhizosphere soil, Soil multifunctionality, Stand ages},
	pages = {3079--3099},
}

Soil microbes play critical roles in supporting multiple ecosystem functions in forests. Their community characteristics are strongly influenced by the soil compartments they occupy (e.g., rhizosphere and bulk soils) as well as stand ages during plantation restoration. However, little is known about whether the effects of microbial communities on soil multifunctionality differ between soil compartments and how these effects are influenced by stand stages.

@article{zheng_tree_2025,
	title = {Tree functional group mediates the effects of nutrient addition on soil nutrients and fungal communities beneath decomposing wood},
	volume = {510},
	issn = {0032-079X, 1573-5036},
	url = {https://link.springer.com/10.1007/s11104-024-06959-2},
	doi = {10.1007/s11104-024-06959-2},
	language = {en},
	number = {1-2},
	urldate = {2026-03-17},
	journal = {Plant and Soil},
	author = {Zheng, Yuxiong and Hu, Zhenhong and Jian, Jinshi and Chen, Ji and Osborne, Brooke B. and Zhou, Guiyao and Xu, Qian and Zheng, Zemei and Ma, Longlong and He, Xian and Bell, Stephen M. and Frew, Adam},
	month = may,
	year = {2025},
	keywords = {Carbon cycling, Nutrient addition experiment, Saprotrophic fungi, Soil nutrient concentrations, Tree functional group, Wood decomposition},
	pages = {797--813},
}

@article{frew_what_2025,
	title = {What does colonisation tell us? {Revisiting} the functional outcomes of root colonisation by arbuscular mycorrhizal fungi},
	volume = {247},
	issn = {0028-646X},
	shorttitle = {What does colonisation tell us?},
	url = {https://pmc.ncbi.nlm.nih.gov/articles/PMC12267904/},
	doi = {10.1111/nph.70284},
	number = {4},
	urldate = {2026-03-18},
	journal = {The New Phytologist},
	author = {Frew, Adam},
	month = aug,
	year = {2025},
	pages = {1572--1578},
}

@article{frew_community_2024,
	title = {Community assembly of root-colonizing arbuscular mycorrhizal fungi: beyond carbon and into defence?},
	volume = {18},
	issn = {1751-7362},
	shorttitle = {Community assembly of root-colonizing arbuscular mycorrhizal fungi},
	url = {https://doi.org/10.1093/ismejo/wrae007},
	doi = {10.1093/ismejo/wrae007},
	abstract = {The arbuscular mycorrhizal (AM) fungi form symbiotic associations with the majority of terrestrial plants in a relationship estimated to be at least 470 million years old [1]. This symbiosis supported the terrestrialization of plants by facilitating their access to belowground nutrients, such as phosphorus. Today, AM fungi associate with most land plants where, as obligate symbionts, they rely entirely on their hosts for access to carbon as carbohydrates and lipids [2]. Yet the AM symbiosis does not exist in isolation. Simultaneous to AM fungal colonization, almost all plant hosts are subject to foliar damage from herbivores and pathogens. These antagonistic relationships are as ubiquitous as the AM symbiosis itself and have had significant impacts on the evolution and diversification of vegetation [3, 4]. Thus, this complex interplay among AM fungi, plants, and their herbivorous and pathogenic antagonists serves as a key driver in the ecological and evolutionary dynamics not only of the individual partners but also of global ecosystems.},
	number = {1},
	urldate = {2026-03-17},
	journal = {The ISME Journal},
	author = {Frew, Adam and Weinberger, Natascha and Powell, Jeff R and Watts-Williams, Stephanie J and Aguilar-Trigueros, Carlos A},
	month = jan,
	year = {2024},
	pages = {wrae007},
}

The arbuscular mycorrhizal (AM) fungi form symbiotic associations with the majority of terrestrial plants in a relationship estimated to be at least 470 million years old [1]. This symbiosis supported the terrestrialization of plants by facilitating their access to belowground nutrients, such as phosphorus. Today, AM fungi associate with most land plants where, as obligate symbionts, they rely entirely on their hosts for access to carbon as carbohydrates and lipids [2]. Yet the AM symbiosis does not exist in isolation. Simultaneous to AM fungal colonization, almost all plant hosts are subject to foliar damage from herbivores and pathogens. These antagonistic relationships are as ubiquitous as the AM symbiosis itself and have had significant impacts on the evolution and diversification of vegetation [3, 4]. Thus, this complex interplay among AM fungi, plants, and their herbivorous and pathogenic antagonists serves as a key driver in the ecological and evolutionary dynamics not only of the individual partners but also of global ecosystems.

@inproceedings{heuck_elevated_2024,
	address = {Australia},
	title = {Elevated {CO2} concentrations play a major role in influencing the functionality of {AM} fungal communities in agroecosystems},
	url = {https://esa2024.org.au/},
	abstract = {Arbuscular mycorrhizal (AM) fungi are important symbionts of most plants that can enhance nutrient uptake and resistance to abiotic stressors. Considering the potential benefits they offer plants, AM fungi could significantly contribute to sustainable agriculture, particularly as we face new challenges associated with climate change. However, our limited understanding of how agricultural practices affect the diversity and functions of AM fungi under climate change obstructs their effective use. We assessed how AM fungal communities, shaped by organic and conventional farming, influenced Sorghum bicolor performance under elevated CO2 (eCO2), water limitation, and their combination. Plant growth and development was analysed alongside AM fungal community composition using DNA metabarcoding.
Under both, water-limited and non-water-limited conditions, we observed considerable differences between eCO2 and ambient CO2 (aCO2) concentrations. Plants associated with AM fungi from conventional management produced 63\% more biomass under eCO2, while those with AM fungi from organic management produced 39\% more biomass under aCO2. Phosphorus concentrations followed a similar trend, increasing by 48\% under eCO2 and 25\% under aCO2.
Our findings suggest that AM fungi shaped by conventional management offer greater benefits to plants under eCO2, while the reverse is true under aCO2. This may be due to the fast-colonizing fungi of conventional systems more efficiently capitalising on higher carbon availability from plants under eCO2. Our study underscores the pivotal role of agricultural management in shaping the functionality of AM fungal communities for crops under climate change, emphasising the impact of eCO2 on the AM symbiosis.},
	language = {en},
	urldate = {2026-03-17},
	author = {Heuck, Meike Katharina and Powell, Jeff and Kath, Jarrod and Birnbaum, Christina and Frew, Adam},
	month = jan,
	year = {2024},
	note = {Num Pages: 1},
	pages = {319--319},
}

Arbuscular mycorrhizal (AM) fungi are important symbionts of most plants that can enhance nutrient uptake and resistance to abiotic stressors. Considering the potential benefits they offer plants, AM fungi could significantly contribute to sustainable agriculture, particularly as we face new challenges associated with climate change. However, our limited understanding of how agricultural practices affect the diversity and functions of AM fungi under climate change obstructs their effective use. We assessed how AM fungal communities, shaped by organic and conventional farming, influenced Sorghum bicolor performance under elevated CO2 (eCO2), water limitation, and their combination. Plant growth and development was analysed alongside AM fungal community composition using DNA metabarcoding. Under both, water-limited and non-water-limited conditions, we observed considerable differences between eCO2 and ambient CO2 (aCO2) concentrations. Plants associated with AM fungi from conventional management produced 63% more biomass under eCO2, while those with AM fungi from organic management produced 39% more biomass under aCO2. Phosphorus concentrations followed a similar trend, increasing by 48% under eCO2 and 25% under aCO2. Our findings suggest that AM fungi shaped by conventional management offer greater benefits to plants under eCO2, while the reverse is true under aCO2. This may be due to the fast-colonizing fungi of conventional systems more efficiently capitalising on higher carbon availability from plants under eCO2. Our study underscores the pivotal role of agricultural management in shaping the functionality of AM fungal communities for crops under climate change, emphasising the impact of eCO2 on the AM symbiosis.

@article{heuck_evaluating_2024,
	title = {Evaluating the {Usefulness} of the {C}-{S}-{R} {Framework} for {Understanding} {AM} {Fungal} {Responses} to {Climate} {Change} in {Agroecosystems}},
	volume = {30},
	copyright = {© 2024 John Wiley \& Sons Ltd.},
	issn = {1365-2486},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.17566},
	doi = {10.1111/gcb.17566},
	abstract = {Arbuscular mycorrhizal (AM) fungi play a key role in terrestrial ecosystems by forming symbiotic relationships with plants and may confer benefits for sustainable agriculture, by reducing reliance on harmful fertiliser and pesticide inputs and enhancing plant resilience against insect herbivores. Despite their ecological importance, critical gaps in understanding AM fungal ecology limit predictions of their responses to global change in agroecosystems. However, predicting climate change impacts on AM fungi is important for maintaining crop productivity and ecosystem stability. Efforts to classify AM fungi based on functional traits, such as the competitor, stress-tolerator, ruderal (C-S-R) framework, aim to address these gaps but face challenges due to the obligate symbiotic nature of the fungi. As the framework is still widely used, we evaluate its applicability in predicting global change impacts on AM fungal communities in agroecosystems. Chagnon's adaptation of the C-S-R framework for AM fungi aligns with some study outcomes (e.g., under the context of water limitation) but faces challenges when used in complex climate change scenarios, varying agricultural conditions and/or extreme climatic conditions. The reliance on a limited dataset to classify AM fungal families further limits accurate predictions of AM fungal community dynamics. Trait data collection could support a nuanced understanding of AM fungi and leveraging AM fungal databases could streamline data management and analysis, enhancing efforts to clarify AM fungal responses to environmental change and guide ecosystem management practices. Thus, while the C-S-R framework holds promise, it requires additional AM fungal trait data for validation and improvement of its predictive power. Conclusively, before designing experiments based on life-history strategies and developing new frameworks tailored to AM fungi a critical first step is to gain a comprehensive understanding of their traits.},
	language = {en},
	number = {11},
	urldate = {2026-03-17},
	journal = {Global Change Biology},
	author = {Heuck, Meike Katharina and Powell, Jeff R. and Kath, Jarrod and Birnbaum, Christina and Frew, Adam},
	year = {2024},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/gcb.17566},
	keywords = {AM fungal traits, Arbuscular mycorrhizal fungi, C-S-R framework, agriculture, climate change, life-history strategies},
	pages = {e17566},
}

Arbuscular mycorrhizal (AM) fungi play a key role in terrestrial ecosystems by forming symbiotic relationships with plants and may confer benefits for sustainable agriculture, by reducing reliance on harmful fertiliser and pesticide inputs and enhancing plant resilience against insect herbivores. Despite their ecological importance, critical gaps in understanding AM fungal ecology limit predictions of their responses to global change in agroecosystems. However, predicting climate change impacts on AM fungi is important for maintaining crop productivity and ecosystem stability. Efforts to classify AM fungi based on functional traits, such as the competitor, stress-tolerator, ruderal (C-S-R) framework, aim to address these gaps but face challenges due to the obligate symbiotic nature of the fungi. As the framework is still widely used, we evaluate its applicability in predicting global change impacts on AM fungal communities in agroecosystems. Chagnon's adaptation of the C-S-R framework for AM fungi aligns with some study outcomes (e.g., under the context of water limitation) but faces challenges when used in complex climate change scenarios, varying agricultural conditions and/or extreme climatic conditions. The reliance on a limited dataset to classify AM fungal families further limits accurate predictions of AM fungal community dynamics. Trait data collection could support a nuanced understanding of AM fungi and leveraging AM fungal databases could streamline data management and analysis, enhancing efforts to clarify AM fungal responses to environmental change and guide ecosystem management practices. Thus, while the C-S-R framework holds promise, it requires additional AM fungal trait data for validation and improvement of its predictive power. Conclusively, before designing experiments based on life-history strategies and developing new frameworks tailored to AM fungi a critical first step is to gain a comprehensive understanding of their traits.

@article{frew_herbivory-driven_2024,
	title = {Herbivory-driven shifts in arbuscular mycorrhizal fungal community assembly: increased fungal competition and plant phosphorus benefits},
	volume = {241},
	copyright = {© 2023 The Authors. New Phytologist © 2023 New Phytologist Foundation},
	issn = {1469-8137},
	shorttitle = {Herbivory-driven shifts in arbuscular mycorrhizal fungal community assembly},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/nph.19474},
	doi = {10.1111/nph.19474},
	language = {en},
	number = {5},
	urldate = {2026-03-17},
	journal = {New Phytologist},
	author = {Frew, Adam and Öpik, Maarja and Oja, Jane and Vahter, Tanel and Hiiesalu, Inga and Aguilar-Trigueros, Carlos A.},
	year = {2024},
	note = {\_eprint: https://nph.onlinelibrary.wiley.com/doi/pdf/10.1111/nph.19474},
	keywords = {arbuscular mycorrhizal fungal diversity, competition, insect herbivores, microbial communities, phylogenetic diversity},
	pages = {1891--1899},
}

@article{frew_increasing_2024,
	title = {Increasing {Phylogenetic} {Clustering} of {Arbuscular} {Mycorrhizal} {Fungal} {Communities} in {Roots} {Explains} {Enhanced} {Plant} {Growth} and {Phosphorus} {Uptake}},
	volume = {87},
	issn = {1432-184X},
	url = {https://doi.org/10.1007/s00248-024-02457-1},
	doi = {10.1007/s00248-024-02457-1},
	abstract = {Temporal variation during the assembly of arbuscular mycorrhizal (AM) fungal communities within plant roots have been posited as critical drivers of the plant-fungal symbiotic outcomes. However, functional implications of these dynamics for the host plant remain poorly understood. We conducted a controlled pot experiment with Sorghum bicolor to investigate how temporal shifts in AM fungal community composition and phylogenetic diversity influence plant growth and phosphorus responses to the symbiosis. We characterised the root-colonising AM fungal communities across three time points and explored their community assembly processes by analysing their phylogenetic diversity and employing joint species distribution modelling with the Hierarchical Modelling of Species Communities (HMSC) framework. We found strong AM fungal turnover through time with a high phylogenetic signal, indicating recruitment of phylogenetically clustered AM fungal species in the host. This temporal phylogenetic clustering of communities coincided with marked increases in plant biomass and phosphorus responses to the AM fungal symbiosis, suggesting that host selection for specific fungi may be a key determinant of these benefits.},
	language = {en},
	number = {1},
	urldate = {2026-03-17},
	journal = {Microbial Ecology},
	author = {Frew, Adam and Aguilar-Trigueros, Carlos A.},
	month = nov,
	year = {2024},
	keywords = {Arbuscular mycorrhiza, Community assembly, Phylogenetic diversity, Sorghum bicolor},
	pages = {139},
}

Temporal variation during the assembly of arbuscular mycorrhizal (AM) fungal communities within plant roots have been posited as critical drivers of the plant-fungal symbiotic outcomes. However, functional implications of these dynamics for the host plant remain poorly understood. We conducted a controlled pot experiment with Sorghum bicolor to investigate how temporal shifts in AM fungal community composition and phylogenetic diversity influence plant growth and phosphorus responses to the symbiosis. We characterised the root-colonising AM fungal communities across three time points and explored their community assembly processes by analysing their phylogenetic diversity and employing joint species distribution modelling with the Hierarchical Modelling of Species Communities (HMSC) framework. We found strong AM fungal turnover through time with a high phylogenetic signal, indicating recruitment of phylogenetically clustered AM fungal species in the host. This temporal phylogenetic clustering of communities coincided with marked increases in plant biomass and phosphorus responses to the AM fungal symbiosis, suggesting that host selection for specific fungi may be a key determinant of these benefits.

@article{field_innovation_2024,
	title = {Innovation in plant and soil sciences to tackle critical global challenges},
	volume = {6},
	copyright = {© 2024 The Authors. Plants, People, Planet published by John Wiley \& Sons Ltd on behalf of New Phytologist Foundation.},
	issn = {2572-2611},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/ppp3.10520},
	doi = {10.1002/ppp3.10520},
	abstract = {Innovations in plant and soil sciences are revolutionising our approach to sustainability, offering solutions with broad societal impacts. Discoveries in these fields hold great potential for combatting, mitigating and adapting to climate change; enhancing food security; and revitalising urban environments. By harnessing the power of plants and the soils they grow in, it is possible to cultivate resilience in the face of environmental challenges, informing policy and practice, and thereby guiding us towards a more sustainable future.},
	number = {6},
	urldate = {2026-03-17},
	journal = {PLANTS, PEOPLE, PLANET},
	author = {Field, Katie J. and Carrillo, Yolima and Campbell, Stuart A. and Ton, Jurriaan and Frew, Adam},
	year = {2024},
	note = {\_eprint: https://nph.onlinelibrary.wiley.com/doi/pdf/10.1002/ppp3.10520},
	keywords = {adaptation, climate change, global challenges, mitigation, plant science, soil science, sustainability},
	pages = {1153--1158},
}

Innovations in plant and soil sciences are revolutionising our approach to sustainability, offering solutions with broad societal impacts. Discoveries in these fields hold great potential for combatting, mitigating and adapting to climate change; enhancing food security; and revitalising urban environments. By harnessing the power of plants and the soils they grow in, it is possible to cultivate resilience in the face of environmental challenges, informing policy and practice, and thereby guiding us towards a more sustainable future.

@article{birnbaum_integrating_2024,
	title = {Integrating soil microbial communities into fundamental ecology, conservation, and restoration: examples from {Australia}},
	volume = {241},
	copyright = {© 2023 The Authors. New Phytologist © 2023 New Phytologist Foundation},
	issn = {1469-8137},
	shorttitle = {Integrating soil microbial communities into fundamental ecology, conservation, and restoration},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/nph.19440},
	doi = {10.1111/nph.19440},
	language = {en},
	number = {3},
	urldate = {2026-03-17},
	journal = {New Phytologist},
	author = {Birnbaum, Christina and Dearnaley, John and Egidi, Eleonora and Frew, Adam and Hopkins, Anna and Powell, Jeff and Aguilar-Trigueros, Carlos and Liddicoat, Craig and Albornoz, Felipe and Heuck, Meike K. and Dadzie, Frederick A. and Florence, Luke and Singh, Pankaj and Mansfield, Tomas and Rajapaksha, Kumari and Stewart, Jana and Rallo, Paola and Peddle, Shawn D. and Chiarenza, Giancarlo},
	year = {2024},
	note = {\_eprint: https://nph.onlinelibrary.wiley.com/doi/pdf/10.1111/nph.19440},
	keywords = {Australia, conservation, mycorrhizal fungi, restoration, soil microbes},
	pages = {974--981},
}

@article{luo_mechanisms_2024,
	title = {Mechanisms of soil organic carbon stabilization and its response to conversion of primary natural broadleaf forests to secondary forests and plantation forests},
	volume = {240},
	issn = {0341-8162},
	url = {https://www.sciencedirect.com/science/article/pii/S0341816224002182},
	doi = {10.1016/j.catena.2024.108021},
	abstract = {Soil organic carbon (SOC) is highly susceptible to land cover change. The assessment of SOC stabilization mechanisms is therefore crucial to understand the carbon (C) dynamic in terrestrial ecosystems. However, the mechanisms underlying the stabilization of SOC following forest conversion of primary natural broadleaf forests (BF) to secondary forests (SF) and plantation forests (PF) remain unclear. Here, we investigated the soil aggregate distribution and associated SOC concentration, and the dynamics of iron (Fe) and aluminum (Al) oxides in BF (24 sites), SF (25 sites), and PF (16 sites) soils in subtropical China. Results showed that SOC concentrations both in the bulk soil and within aggregates significantly decreased when BF were converted to SF and PF, and these reductions were more pronounced in the topsoil (0–10 cm) than those in the subsoil (10–30 cm). Soil macroaggregates ({\textgreater}250 μm) accounted for the largest proportions of aggregate fractions by mass (40.3 \%, 38.9 \%, and 39.4 \%) and their associated SOC decreased with forest conversion and contributed the greatest proportions of C (11.1 g kg−1, 10.2 g kg−1, and 9.6 g kg−1) to the bulk soil C in BF, SF, and PF, respectively, suggesting that the SOC within macroaggregate contributed to the largest decrease in SOC. The decreases in SOC within macroaggregate, especially with the conversion of BF to PF, were mainly ascribed to the reductions of tree biomass, C stocks of litter and root, and the decreases in the concentration of the Fed/Ald and Fep/Alp oxides but not the concentration of total Fe/Al oxides in gravel and soil. These findings recommend that mixtures of suitable native broadleaf species (e.g., BF species) with plantation species to enhance SOC stabilization in PF, thereby improving the stabilization and sequestration of SOC. Overall, these results help explain why soil C stabilization decreases following forest conversion, and propose an approach for the rehabilitation of plantation forests.},
	urldate = {2026-03-17},
	journal = {CATENA},
	author = {Luo, Xianzhen and Zhang, Rui and Zhang, Lingling and Frew, Adam and Yu, Hanxia and Hou, Enqing and Wen, Dazhi},
	month = may,
	year = {2024},
	keywords = {Aggregates, Forest conversion, Iron or aluminum oxides, Organic carbon sequestration, Subtropical forests},
	pages = {108021},
}

Soil organic carbon (SOC) is highly susceptible to land cover change. The assessment of SOC stabilization mechanisms is therefore crucial to understand the carbon (C) dynamic in terrestrial ecosystems. However, the mechanisms underlying the stabilization of SOC following forest conversion of primary natural broadleaf forests (BF) to secondary forests (SF) and plantation forests (PF) remain unclear. Here, we investigated the soil aggregate distribution and associated SOC concentration, and the dynamics of iron (Fe) and aluminum (Al) oxides in BF (24 sites), SF (25 sites), and PF (16 sites) soils in subtropical China. Results showed that SOC concentrations both in the bulk soil and within aggregates significantly decreased when BF were converted to SF and PF, and these reductions were more pronounced in the topsoil (0–10 cm) than those in the subsoil (10–30 cm). Soil macroaggregates (\textgreater250 μm) accounted for the largest proportions of aggregate fractions by mass (40.3 %, 38.9 %, and 39.4 %) and their associated SOC decreased with forest conversion and contributed the greatest proportions of C (11.1 g kg−1, 10.2 g kg−1, and 9.6 g kg−1) to the bulk soil C in BF, SF, and PF, respectively, suggesting that the SOC within macroaggregate contributed to the largest decrease in SOC. The decreases in SOC within macroaggregate, especially with the conversion of BF to PF, were mainly ascribed to the reductions of tree biomass, C stocks of litter and root, and the decreases in the concentration of the Fed/Ald and Fep/Alp oxides but not the concentration of total Fe/Al oxides in gravel and soil. These findings recommend that mixtures of suitable native broadleaf species (e.g., BF species) with plantation species to enhance SOC stabilization in PF, thereby improving the stabilization and sequestration of SOC. Overall, these results help explain why soil C stabilization decreases following forest conversion, and propose an approach for the rehabilitation of plantation forests.

@article{wang_neighbourhood_2024,
	title = {Neighbourhood diversity effects on insect herbivory: {Plant} leaf traits mediate associational resistance},
	volume = {112},
	copyright = {© 2024 The Author(s). Journal of Ecology © 2024 British Ecological Society.},
	issn = {1365-2745},
	shorttitle = {Neighbourhood diversity effects on insect herbivory},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/1365-2745.14405},
	doi = {10.1111/1365-2745.14405},
	abstract = {The vulnerability of trees to insect herbivory can be influenced by forest structure and diversity. Associational resistance theory posits that trees surrounded by diverse neighbours are likely to suffer reduced herbivory. However, the underlying mechanisms of this effect are debated, with accumulating evidence suggesting that leaf traits could mediate the strength and direction of the diversity-herbivory relationships. To determine the role of tree trait variation in mediating this relationship, we measured leaf herbivory and nine morphological and nutritional leaf traits known to influence herbivory on 394 focal trees of twelve species cultivated in monocultures and mixtures of four, eight, and sixteen species in a 4-year-old large-scale manipulated tree diversity experiment. A reduction in the proportion of focal trees in species-rich neighbourhoods resulted in increased leaf carbon: nitrogen ratio of focal trees, which mediated a reduction in insect herbivory. Moreover, an increase in plant height apparency, defined as the disparity in total height between a focal tree and its closest neighbours, indirectly amplified herbivory by reducing leaf phosphorus concentration. Synthesis: The study suggests that neighbourhood diversity and physical structure can indirectly affect herbivory on a focal plant by modifying its leaf trait. Accounting for the functional differences between forests could enhance our understanding of diversity–herbivory relationships.},
	language = {en},
	number = {11},
	urldate = {2026-03-18},
	journal = {Journal of Ecology},
	author = {Wang, Zhenyu and Feng, Lixuan and Frew, Adam and Lu, Anqi and Yu, Zaipeng and Huang, Zhiqun},
	year = {2024},
	note = {\_eprint: https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2745.14405},
	keywords = {NaBEF experiment, associational resistance, biodiversity and ecosystem functioning, plant apparency, plant functional traits, plant-herbivore interactions, subtropical forest},
	pages = {2613--2623},
}

The vulnerability of trees to insect herbivory can be influenced by forest structure and diversity. Associational resistance theory posits that trees surrounded by diverse neighbours are likely to suffer reduced herbivory. However, the underlying mechanisms of this effect are debated, with accumulating evidence suggesting that leaf traits could mediate the strength and direction of the diversity-herbivory relationships. To determine the role of tree trait variation in mediating this relationship, we measured leaf herbivory and nine morphological and nutritional leaf traits known to influence herbivory on 394 focal trees of twelve species cultivated in monocultures and mixtures of four, eight, and sixteen species in a 4-year-old large-scale manipulated tree diversity experiment. A reduction in the proportion of focal trees in species-rich neighbourhoods resulted in increased leaf carbon: nitrogen ratio of focal trees, which mediated a reduction in insect herbivory. Moreover, an increase in plant height apparency, defined as the disparity in total height between a focal tree and its closest neighbours, indirectly amplified herbivory by reducing leaf phosphorus concentration. Synthesis: The study suggests that neighbourhood diversity and physical structure can indirectly affect herbivory on a focal plant by modifying its leaf trait. Accounting for the functional differences between forests could enhance our understanding of diversity–herbivory relationships.

@article{yu_upgrade_2024,
	title = {Upgrade from aerated static pile to agitated bed systems promotes lignocellulose degradation in large-scale composting through enhanced microbial functional diversity},
	volume = {144},
	issn = {1001-0742},
	url = {https://www.sciencedirect.com/science/article/pii/S1001074223004060},
	doi = {10.1016/j.jes.2023.09.008},
	abstract = {Composting presents a viable management solution for lignocellulose-rich municipal solid waste. However, our understanding about the microbial metabolic mechanisms involved in the biodegradation of lignocellulose, particularly in industrial-scale composting plants, remains limited. This study employed metaproteomics to compare the impact of upgrading from aerated static pile (ASP) to agitated bed (AB) systems on physicochemical parameters, lignocellulose biodegradation, and microbial metabolic pathways during large-scale biowaste composting process, marking the first investigation of its kind. The degradation rates of lignocellulose including cellulose, hemicellulose, and lignin were significantly higher in AB (8.21\%-32.54\%, 10.21\%-39.41\%, and 6.21\%-26.78\%) than those (5.72\%-23.15\%, 7.01\%-33.26\%, and 4.79\%-19.76\%) in ASP at three thermal stages, respectively. The AB system in comparison to ASP increased the carbohydrate-active enzymes (CAZymes) abundance and production of the three essential enzymes required for lignocellulose decomposition involving a mixture of bacteria and fungi (i.e., Actinobacteria, Bacilli, Sordariomycetes and Eurotiomycetes). Conversely, ASP primarily produced exoglucanase and β-glucosidase via fungi (i.e., Ascomycota). Moreover, AB effectively mitigated microbial stress caused by acetic acid accumulation by regulating the key enzymes involved in acetate conversion, including acetyl-coenzyme A synthetase and acetate kinase. Overall, the AB upgraded from ASP facilitated the lignocellulose degradation and fostered more diverse functional microbial communities in large-scale composting. Our findings offer a valuable scientific basis to guide the engineering feasibility and environmental sustainability for large-scale industrial composting plants for treating lignocellulose-rich waste. These findings have important implications for establishing green sustainable development models (e.g., a circular economy based on material recovery) and for achieving sustainable development goals.},
	urldate = {2026-03-17},
	journal = {Journal of Environmental Sciences},
	author = {Yu, Hanxia and Xiao, Haoyan and Deng, Huiyu and Frew, Adam and Hossain, Md. Akhter and Tan, Wenbing and Xi, Beidou},
	month = oct,
	year = {2024},
	keywords = {Bacterial and fungal community, Large-scale composting, Lignocellulose degradation, Metaproteomic analysis, Microbial metabolism},
	pages = {55--66},
}

Composting presents a viable management solution for lignocellulose-rich municipal solid waste. However, our understanding about the microbial metabolic mechanisms involved in the biodegradation of lignocellulose, particularly in industrial-scale composting plants, remains limited. This study employed metaproteomics to compare the impact of upgrading from aerated static pile (ASP) to agitated bed (AB) systems on physicochemical parameters, lignocellulose biodegradation, and microbial metabolic pathways during large-scale biowaste composting process, marking the first investigation of its kind. The degradation rates of lignocellulose including cellulose, hemicellulose, and lignin were significantly higher in AB (8.21%-32.54%, 10.21%-39.41%, and 6.21%-26.78%) than those (5.72%-23.15%, 7.01%-33.26%, and 4.79%-19.76%) in ASP at three thermal stages, respectively. The AB system in comparison to ASP increased the carbohydrate-active enzymes (CAZymes) abundance and production of the three essential enzymes required for lignocellulose decomposition involving a mixture of bacteria and fungi (i.e., Actinobacteria, Bacilli, Sordariomycetes and Eurotiomycetes). Conversely, ASP primarily produced exoglucanase and β-glucosidase via fungi (i.e., Ascomycota). Moreover, AB effectively mitigated microbial stress caused by acetic acid accumulation by regulating the key enzymes involved in acetate conversion, including acetyl-coenzyme A synthetase and acetate kinase. Overall, the AB upgraded from ASP facilitated the lignocellulose degradation and fostered more diverse functional microbial communities in large-scale composting. Our findings offer a valuable scientific basis to guide the engineering feasibility and environmental sustainability for large-scale industrial composting plants for treating lignocellulose-rich waste. These findings have important implications for establishing green sustainable development models (e.g., a circular economy based on material recovery) and for achieving sustainable development goals.

@article{frew_australia_2023,
	title = {Australia offers unique insight into the ecology of arbuscular mycorrhizal fungi: {An} opportunity not to be lost},
	volume = {48},
	copyright = {© 2023 The Authors. Austral Ecology published by John Wiley \& Sons Australia, Ltd on behalf of Ecological Society of Australia.},
	issn = {1442-9993},
	shorttitle = {Australia offers unique insight into the ecology of arbuscular mycorrhizal fungi},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/aec.13451},
	doi = {10.1111/aec.13451},
	abstract = {Typified by ancient soils and unique assemblages of flora, Australia provides opportunities to expand our understanding of arbuscular mycorrhizal (AM) fungi. Despite their ubiquity, key aspects of Australian AM fungal ecology remain buried due to our limited knowledge of their biogeography and their potential adaptation to Australia's environmental conditions. This knowledge gap is particularly extraordinary given that the characteristics of the Australian environment are likely to provide unique insights into AM fungal ecology and evolution. Extensive exploration of the diversity and distribution of AM fungi across the continent is overdue. In pursuit of this goal, ecologists should employ the most effective and pragmatic molecular approaches, while making use of well-curated databases. We urge researchers to examine the biogeography of Australian AM fungi meaningfully, leveraging the distinctive attributes of Australian landscapes, such as the demographics of plant mycorrhizal types and the characteristic interplay with fire. Documenting AM fungal communities across Australia will not only provide unique insights into their ecology but is also pivotal to being able to incorporate these organisms into land management for conservation, restoration and sustainable agriculture.},
	language = {en},
	number = {8},
	urldate = {2026-03-17},
	journal = {Austral Ecology},
	author = {Frew, Adam and Aguilar-Trigueros, Carlos A.},
	year = {2023},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/aec.13451},
	keywords = {Australia, SSU, arbuscular mycorrhizal fungi, dual mycorrhizal, fire ecology, fungal ecology, metabarcoding},
	pages = {1713--1720},
}

Typified by ancient soils and unique assemblages of flora, Australia provides opportunities to expand our understanding of arbuscular mycorrhizal (AM) fungi. Despite their ubiquity, key aspects of Australian AM fungal ecology remain buried due to our limited knowledge of their biogeography and their potential adaptation to Australia's environmental conditions. This knowledge gap is particularly extraordinary given that the characteristics of the Australian environment are likely to provide unique insights into AM fungal ecology and evolution. Extensive exploration of the diversity and distribution of AM fungi across the continent is overdue. In pursuit of this goal, ecologists should employ the most effective and pragmatic molecular approaches, while making use of well-curated databases. We urge researchers to examine the biogeography of Australian AM fungi meaningfully, leveraging the distinctive attributes of Australian landscapes, such as the demographics of plant mycorrhizal types and the characteristic interplay with fire. Documenting AM fungal communities across Australia will not only provide unique insights into their ecology but is also pivotal to being able to incorporate these organisms into land management for conservation, restoration and sustainable agriculture.

@article{ng_belowground_2023,
	title = {Belowground crop responses to root herbivory are associated with the community structure of native arbuscular mycorrhizal fungi},
	volume = {185},
	issn = {0929-1393},
	url = {https://www.sciencedirect.com/science/article/pii/S0929139322004139},
	doi = {10.1016/j.apsoil.2022.104797},
	abstract = {There is growing interest in managing arbuscular mycorrhizal (AM) fungi in agriculture to support plant production. These fungi can support crop growth and nutrient uptake, but also affect plant-herbivore interactions. While our understanding of how AM fungi affect plant responses to herbivory advances, it is less clear how different naturally-occurring (native) fungal communities differentially influence crop responses to root-feeding insects. To explore this, plants (Sorghum bicolor) were grown in a glasshouse experiment without AM fungi (‘no AM fungi’) or with one of three natural soil inocula sourced either from a sclerophyll forest (‘forest inoculum’), a cropped field (‘field inoculum’), or a field in fallow (‘fallow inoculum’), while half the plants were subjected to a root herbivore (Dermolepida albohirtum). We assessed the effects of soil inoculum and root herbivory on root-colonising AM fungal diversity, plant growth, and nutrient content. Root herbivory did not affect AM fungal diversity or composition. Plants grown with the field or fallow inocula were both dominated by the genera Glomus and Claroideoglomus. These plants exhibited reduced biomass in response to inoculation, but were not impacted by root herbivory. In contrast, plants with the forest inoculum had AM fungal communities dominated by Paraglomus and Ambispora. When subjected to root herbivory, the forest inoculated plants and plants without AM fungi exhibited reductions of 44 \% and 61 \% in root biomass, and reductions of 65 \% and 59 \% in root phosphorus, respectively. Our study shows inoculation-driven plant responses to root herbivory that were associated with the community structure of their root-colonising AM fungi. Results suggest associations with communities dominated by Claroideoglomus and Glomus may mitigate the impacts of a root-feeding insect. More exploration of how natural assemblages of AM fungi mediate plant-herbivore interactions is needed if we are to effectively manage soil fungi in agriculture.},
	urldate = {2026-03-17},
	journal = {Applied Soil Ecology},
	author = {Ng, Anna and Wilson, Bree A. L. and Frew, Adam},
	month = may,
	year = {2023},
	keywords = {Arbuscular mycorrhizal fungi, Dermolepida albohirtum, Plant defence, Root herbivory},
	pages = {104797},
}

There is growing interest in managing arbuscular mycorrhizal (AM) fungi in agriculture to support plant production. These fungi can support crop growth and nutrient uptake, but also affect plant-herbivore interactions. While our understanding of how AM fungi affect plant responses to herbivory advances, it is less clear how different naturally-occurring (native) fungal communities differentially influence crop responses to root-feeding insects. To explore this, plants (Sorghum bicolor) were grown in a glasshouse experiment without AM fungi (‘no AM fungi’) or with one of three natural soil inocula sourced either from a sclerophyll forest (‘forest inoculum’), a cropped field (‘field inoculum’), or a field in fallow (‘fallow inoculum’), while half the plants were subjected to a root herbivore (Dermolepida albohirtum). We assessed the effects of soil inoculum and root herbivory on root-colonising AM fungal diversity, plant growth, and nutrient content. Root herbivory did not affect AM fungal diversity or composition. Plants grown with the field or fallow inocula were both dominated by the genera Glomus and Claroideoglomus. These plants exhibited reduced biomass in response to inoculation, but were not impacted by root herbivory. In contrast, plants with the forest inoculum had AM fungal communities dominated by Paraglomus and Ambispora. When subjected to root herbivory, the forest inoculated plants and plants without AM fungi exhibited reductions of 44 % and 61 % in root biomass, and reductions of 65 % and 59 % in root phosphorus, respectively. Our study shows inoculation-driven plant responses to root herbivory that were associated with the community structure of their root-colonising AM fungi. Results suggest associations with communities dominated by Claroideoglomus and Glomus may mitigate the impacts of a root-feeding insect. More exploration of how natural assemblages of AM fungi mediate plant-herbivore interactions is needed if we are to effectively manage soil fungi in agriculture.

@article{greenwood_fire_2023,
	title = {Fire shapes fungal guild diversity and composition through direct and indirect pathways},
	volume = {32},
	copyright = {© 2023 The Authors. Molecular Ecology published by John Wiley \& Sons Ltd.},
	issn = {1365-294X},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/mec.17068},
	doi = {10.1111/mec.17068},
	abstract = {Fire has shaped global ecosystems for millennia by directly killing organisms and indirectly altering habitats and resources. All terrestrial ecosystems, including fire-prone ecosystems, rely on soil-inhabiting fungi, where they play vital roles in ecological processes. Yet our understanding of how fire regimes influence soil fungi remains limited and our knowledge of these interactions in semiarid landscapes is virtually absent. We collected soil samples and vegetation measurements from sites across a gradient in time-since-fire ages (0–75 years-since-fire) and fire frequency (burnt 0–5 times during the recent 29-year period) in a semiarid heathland of south-eastern Australia. We characterized fungal communities using ITS amplicon-sequencing and assigned fungi taxonomically to trophic guilds. We used structural equation models to examine direct, indirect and total effects of time-since-fire and fire frequency on total fungal, ectomycorrhizal, saprotrophic and pathogenic richness. We used multivariate analyses to investigate how total fungal, ectomycorrhizal, saprotrophic and pathogenic species composition differed between post-fire successional stages and fire frequency classes. Time-since-fire was an important driver of saprotrophic richness; directly, saprotrophic richness increased with time-since-fire, and indirectly, saprotrophic richness declined with time-since-fire (resulting in a positive total effect), mediated through the impact of fire on substrates. Frequently burnt sites had lower numbers of saprotrophic and pathogenic species. Post-fire successional stages and fire frequency classes were characterized by distinct fungal communities, with large differences in ectomycorrhizal species composition. Understanding the complex responses of fungal communities to fire can be improved by exploring how the effects of fire flow through ecosystems. Diverse fire histories may be important for maintaining the functional diversity of fungi in semiarid regions.},
	language = {en},
	number = {17},
	urldate = {2026-03-17},
	journal = {Molecular Ecology},
	author = {Greenwood, Leanne and Nimmo, Dale G. and Egidi, Eleonora and Price, Jodi N. and McIntosh, Rachel and Frew, Adam},
	year = {2023},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/mec.17068},
	keywords = {fire frequency, fungal composition, fungal ecology, fungal guilds, fungal richness, time-since-fire},
	pages = {4921--4939},
}

Fire has shaped global ecosystems for millennia by directly killing organisms and indirectly altering habitats and resources. All terrestrial ecosystems, including fire-prone ecosystems, rely on soil-inhabiting fungi, where they play vital roles in ecological processes. Yet our understanding of how fire regimes influence soil fungi remains limited and our knowledge of these interactions in semiarid landscapes is virtually absent. We collected soil samples and vegetation measurements from sites across a gradient in time-since-fire ages (0–75 years-since-fire) and fire frequency (burnt 0–5 times during the recent 29-year period) in a semiarid heathland of south-eastern Australia. We characterized fungal communities using ITS amplicon-sequencing and assigned fungi taxonomically to trophic guilds. We used structural equation models to examine direct, indirect and total effects of time-since-fire and fire frequency on total fungal, ectomycorrhizal, saprotrophic and pathogenic richness. We used multivariate analyses to investigate how total fungal, ectomycorrhizal, saprotrophic and pathogenic species composition differed between post-fire successional stages and fire frequency classes. Time-since-fire was an important driver of saprotrophic richness; directly, saprotrophic richness increased with time-since-fire, and indirectly, saprotrophic richness declined with time-since-fire (resulting in a positive total effect), mediated through the impact of fire on substrates. Frequently burnt sites had lower numbers of saprotrophic and pathogenic species. Post-fire successional stages and fire frequency classes were characterized by distinct fungal communities, with large differences in ectomycorrhizal species composition. Understanding the complex responses of fungal communities to fire can be improved by exploring how the effects of fire flow through ecosystems. Diverse fire histories may be important for maintaining the functional diversity of fungi in semiarid regions.

@article{heuck_friends_2023,
	title = {Friends to the rescue: using arbuscular mycorrhizal fungi to future-proof {Australian} agriculture},
	volume = {44},
	issn = {1324-4272},
	shorttitle = {Friends to the rescue},
	url = {https://doi.org/10.1071/MA23002},
	doi = {10.1071/MA23002},
	abstract = {With a rising global population and the challenges of climate change, there is an increasing need to find solutions to maintain crop yields in an ecologically sustainable way. Although many studies have focussed on this issue, comparatively few are conducted in the southern hemisphere. This is worrisome because the geographical and geomorphological conditions within Australia differ greatly from the northern hemisphere. To ensure food security, approaches can rely on conventional agricultural methods as well as commercial arbuscular mycorrhizal (AM) fungal inoculants. Both approaches lack the capacity to be successful in the long term or could have unknown negative effects on the naturally occurring microbial communities. We advocate for a sustainable and holistic approach that combines the effective management of functionally diverse AM fungal communities with precision farming techniques while integrating landscape elements into agricultural fields. In addition, landowners and scientists should collaborate and communicate their work with industry and government to take forward the shift to a more-sustainable agriculture. In this way, we will be better able to secure our food production while restoring our soil ecosystems.},
	number = {1},
	urldate = {2026-03-17},
	journal = {Microbiology Australia},
	author = {Heuck, Meike Katharina and Birnbaum, Christina and Frew, Adam},
	month = mar,
	year = {2023},
	pages = {5--8},
}

With a rising global population and the challenges of climate change, there is an increasing need to find solutions to maintain crop yields in an ecologically sustainable way. Although many studies have focussed on this issue, comparatively few are conducted in the southern hemisphere. This is worrisome because the geographical and geomorphological conditions within Australia differ greatly from the northern hemisphere. To ensure food security, approaches can rely on conventional agricultural methods as well as commercial arbuscular mycorrhizal (AM) fungal inoculants. Both approaches lack the capacity to be successful in the long term or could have unknown negative effects on the naturally occurring microbial communities. We advocate for a sustainable and holistic approach that combines the effective management of functionally diverse AM fungal communities with precision farming techniques while integrating landscape elements into agricultural fields. In addition, landowners and scientists should collaborate and communicate their work with industry and government to take forward the shift to a more-sustainable agriculture. In this way, we will be better able to secure our food production while restoring our soil ecosystems.

@article{frew_host_2023,
	title = {Host filtering, not competitive exclusion, may be the main driver of arbuscular mycorrhizal fungal community assembly under high phosphorus},
	volume = {37},
	copyright = {© 2023 The Authors. Functional Ecology published by John Wiley \& Sons Ltd on behalf of British Ecological Society.},
	issn = {1365-2435},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/1365-2435.14349},
	doi = {10.1111/1365-2435.14349},
	abstract = {A major goal in ecology is understanding the factors which determine the diversity and distribution of organisms. The outcome of the symbiotic relationship between plants and arbuscular mycorrhizal (AM) fungi is strongly influenced by soil phosphorus (P) availability. Despite this knowledge, there is still much to uncover about how soil P status can shape the taxonomic and phylogenetic assembly of root-colonising AM fungi. Additionally, there is a paucity of understanding about the implications of these changes for the outcome of the AM symbiosis in terms of plant growth, nutrient status and defence traits. We conducted a factorial pot experiment where sorghum (Sorghum bicolor) was grown under three different P treatments (low, medium and high), in the presence or absence of a natural AM fungal community. By analysing the diversity and community structure of the fungal community colonising roots, we aimed to determine if and how soil P influences the relatedness of these communities and whether competitive exclusion or environmental filtering play a more significant role in their assembly. Additionally, we evaluated the concomitant outcomes for plant growth, nutrient acquisition and defensive chemistry (phenolics). Increasing P availability reduced AM fungal richness and increased community evenness. Root-colonising AM fungal communities under the high P treatment had significantly reduced phylogenetic diversity and comparatively lower mean pairwise distances among all treatments. This indicated that AM fungal communities became more closely related (phylogenetically clustered) with increasing soil P. The mycorrhizal growth and mycorrhizal P responses of plants were positive under low and medium P, but this was lost under high P, however, plant phenolics were increased. Our results suggest that under high P conditions, environmental filtering plays an important role in AM fungal community assembly as host plants alter their selectivity of fungal functional groups prioritising those associated with enhancing plant stress resistance and defences, rather than nutrient acquisition. Here we demonstrated how soil P status can shape taxonomic and phylogenetic assembly of AM fungi and the associated functional outcomes for the host. Read the free Plain Language Summary for this article on the Journal blog.},
	language = {en},
	number = {7},
	urldate = {2026-03-17},
	journal = {Functional Ecology},
	author = {Frew, Adam and Heuck, Meike Katharina and Aguilar-Trigueros, Carlos A.},
	year = {2023},
	note = {\_eprint: https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2435.14349},
	keywords = {arbuscular mycorrhizal fungi, community assembly, phylogenetic diversity, plant defence, plant phosphorus},
	pages = {1856--1869},
}

A major goal in ecology is understanding the factors which determine the diversity and distribution of organisms. The outcome of the symbiotic relationship between plants and arbuscular mycorrhizal (AM) fungi is strongly influenced by soil phosphorus (P) availability. Despite this knowledge, there is still much to uncover about how soil P status can shape the taxonomic and phylogenetic assembly of root-colonising AM fungi. Additionally, there is a paucity of understanding about the implications of these changes for the outcome of the AM symbiosis in terms of plant growth, nutrient status and defence traits. We conducted a factorial pot experiment where sorghum (Sorghum bicolor) was grown under three different P treatments (low, medium and high), in the presence or absence of a natural AM fungal community. By analysing the diversity and community structure of the fungal community colonising roots, we aimed to determine if and how soil P influences the relatedness of these communities and whether competitive exclusion or environmental filtering play a more significant role in their assembly. Additionally, we evaluated the concomitant outcomes for plant growth, nutrient acquisition and defensive chemistry (phenolics). Increasing P availability reduced AM fungal richness and increased community evenness. Root-colonising AM fungal communities under the high P treatment had significantly reduced phylogenetic diversity and comparatively lower mean pairwise distances among all treatments. This indicated that AM fungal communities became more closely related (phylogenetically clustered) with increasing soil P. The mycorrhizal growth and mycorrhizal P responses of plants were positive under low and medium P, but this was lost under high P, however, plant phenolics were increased. Our results suggest that under high P conditions, environmental filtering plays an important role in AM fungal community assembly as host plants alter their selectivity of fungal functional groups prioritising those associated with enhancing plant stress resistance and defences, rather than nutrient acquisition. Here we demonstrated how soil P status can shape taxonomic and phylogenetic assembly of AM fungi and the associated functional outcomes for the host. Read the free Plain Language Summary for this article on the Journal blog.

@article{frew_soil_2023,
	title = {Soil abounds with life–and supports all life above it. {But} {Australian} soils need urgent repair},
	journal = {Conversation},
	author = {Frew, Adam and Birnbaum, Christina and Egidi, Eleonora and Heuck, Meike Katharina},
	month = jan,
	year = {2023},
}

@article{frew_water_2023,
	title = {Water availability alters the community structure of arbuscular mycorrhizal fungi and determines plant mycorrhizal benefit},
	volume = {5},
	copyright = {© 2023 The Authors. Plants, People, Planet published by John Wiley \& Sons Ltd on behalf of New Phytologist Foundation.},
	issn = {2572-2611},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/ppp3.10372},
	doi = {10.1002/ppp3.10372},
	abstract = {Societal Impact Statement The world faces major changes in rainfall patterns and water availability, posing a significant threat to plant productions systems and food security. The arbuscular mycorrhizal (AM) fungi associate with most major crops and can support plant nutrient and water uptake. Here, AM fungi were shown to mitigate the negative effects of low water availability on sorghum growth and phosphorus uptake, an effect that was associated with shifts in the fungal community structure. To realise the potential of AM fungi in sustainable agriculture requires more examination of their interactions with edaphic stresses in crop systems.},
	language = {en},
	number = {5},
	urldate = {2026-03-17},
	journal = {PLANTS, PEOPLE, PLANET},
	author = {Frew, Adam},
	year = {2023},
	note = {\_eprint: https://nph.onlinelibrary.wiley.com/doi/pdf/10.1002/ppp3.10372},
	keywords = {arbuscular mycorrhiza, community structure, fungal community, sorghum, sustainable agriculture, water availability},
	pages = {683--689},
}

Societal Impact Statement The world faces major changes in rainfall patterns and water availability, posing a significant threat to plant productions systems and food security. The arbuscular mycorrhizal (AM) fungi associate with most major crops and can support plant nutrient and water uptake. Here, AM fungi were shown to mitigate the negative effects of low water availability on sorghum growth and phosphorus uptake, an effect that was associated with shifts in the fungal community structure. To realise the potential of AM fungi in sustainable agriculture requires more examination of their interactions with edaphic stresses in crop systems.

@article{frew_plant_2022,
	title = {Plant herbivore protection by arbuscular mycorrhizas: a role for fungal diversity?},
	volume = {233},
	copyright = {© 2021 The Authors. New Phytologist © 2021 New Phytologist Foundation},
	issn = {1469-8137},
	shorttitle = {Plant herbivore protection by arbuscular mycorrhizas},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/nph.17781},
	doi = {10.1111/nph.17781},
	language = {en},
	number = {3},
	urldate = {2026-03-17},
	journal = {New Phytologist},
	author = {Frew, Adam and Antunes, Pedro M. and Cameron, Duncan D. and Hartley, Susan E. and Johnson, Scott N. and Rillig, Matthias C. and Bennett, Alison E.},
	year = {2022},
	note = {\_eprint: https://nph.onlinelibrary.wiley.com/doi/pdf/10.1111/nph.17781},
	keywords = {arbuscular mycorrhizal fungal diversity, insect herbivores, microbial communities, plant defence, resistance, tolerance},
	pages = {1022--1031},
}

@article{frew_root_2022,
	title = {Root herbivory reduces species richness and alters community structure of root-colonising arbuscular mycorrhizal fungi},
	volume = {171},
	issn = {0038-0717},
	url = {https://www.sciencedirect.com/science/article/pii/S0038071722001808},
	doi = {10.1016/j.soilbio.2022.108723},
	abstract = {Belowground insect herbivory is an important interaction that can shape ecological communities above- and belowground. A key component of belowground ecosystems are the arbuscular mycorrhizal (AM) fungi that associate with roots of most terrestrial plants. Despite the shared ecological significance of root herbivores and AM fungi, there is an absence of data on how insect root herbivory affects root-colonising AM fungal diversity. This study explored the impacts of root herbivory (from Dermolepida alborhirtum) on the diversity and community composition of AM fungi colonising plant roots (Dichanthium sericeum) and assessed the effects on plant growth and nutrient uptake. Belowground herbivory significantly altered AM fungal community structure and reduced species richness, potentially removing fungal taxa sensitive to root-herbivore disturbance. Meanwhile, herbivory also reduced root biomass and aboveground phosphorus. These findings demonstrate how belowground herbivores can directly shape AM fungal communities in plant roots.},
	urldate = {2026-03-17},
	journal = {Soil Biology and Biochemistry},
	author = {Frew, Adam},
	month = aug,
	year = {2022},
	keywords = {Arbuscular mycorrhizal fungi, Community composition, Diversity, Root herbivore},
	pages = {108723},
}

Belowground insect herbivory is an important interaction that can shape ecological communities above- and belowground. A key component of belowground ecosystems are the arbuscular mycorrhizal (AM) fungi that associate with roots of most terrestrial plants. Despite the shared ecological significance of root herbivores and AM fungi, there is an absence of data on how insect root herbivory affects root-colonising AM fungal diversity. This study explored the impacts of root herbivory (from Dermolepida alborhirtum) on the diversity and community composition of AM fungi colonising plant roots (Dichanthium sericeum) and assessed the effects on plant growth and nutrient uptake. Belowground herbivory significantly altered AM fungal community structure and reduced species richness, potentially removing fungal taxa sensitive to root-herbivore disturbance. Meanwhile, herbivory also reduced root biomass and aboveground phosphorus. These findings demonstrate how belowground herbivores can directly shape AM fungal communities in plant roots.

@article{johnson_silicon_2022,
	title = {Silicon accumulation suppresses arbuscular mycorrhizal fungal colonisation in the model grass {Brachypodium} distachyon},
	volume = {477},
	issn = {1573-5036},
	url = {https://doi.org/10.1007/s11104-022-05463-9},
	doi = {10.1007/s11104-022-05463-9},
	abstract = {Silicon (Si) accumulation by grasses alleviates diverse biotic and abiotic stresses. Despite this important functional role, we have limited understanding of how root microbial symbionts, such as arbuscular mycorrhizal (AM) fungi, affect Si uptake and even less about how Si supply and accumulation affect AM fungal colonisation. Our objective was to determine the nature of this two–way interaction in the model grass, Brachypodium distachyon.},
	language = {en},
	number = {1},
	urldate = {2026-03-17},
	journal = {Plant and Soil},
	author = {Johnson, Scott N. and Powell, Jeff R. and Frew, Adam and Cibils–Stewart, Ximena},
	month = aug,
	year = {2022},
	keywords = {Arbuscular mycorrhizal fungi, Roots, Silica, Silicification, Soils, Symbiont, Trade-offs},
	pages = {219--232},
}

Silicon (Si) accumulation by grasses alleviates diverse biotic and abiotic stresses. Despite this important functional role, we have limited understanding of how root microbial symbionts, such as arbuscular mycorrhizal (AM) fungi, affect Si uptake and even less about how Si supply and accumulation affect AM fungal colonisation. Our objective was to determine the nature of this two–way interaction in the model grass, Brachypodium distachyon.

@inproceedings{heuck_dig_2022,
	title = {‘{Dig} {Up} {Dirt}’, using citizen science to understand the diversity of beneficial fungi in {Australian} agroecosystems},
	author = {Heuck, MK and Birnbaum, C and Kath, J and Powell, J and Frew, A},
	year = {2022},
}

@article{frew_aboveground_2021,
	title = {Aboveground herbivory suppresses the arbuscular mycorrhizal symbiosis, reducing plant phosphorus uptake},
	volume = {168},
	issn = {0929-1393},
	url = {https://www.sciencedirect.com/science/article/pii/S0929139321002560},
	doi = {10.1016/j.apsoil.2021.104133},
	abstract = {Most terrestrial plants form associations with arbuscular mycorrhizal (AM) fungi, which are soil-dwelling microbial symbionts that provide plants with soil nutrients, while plants supply the fungi with carbon. The majority of these plants are also subject to herbivory from insects, thus tripartite interactions between insect herbivores, plants, and AM fungi are ubiquitous. This study assessed how aboveground herbivory from a generalist insect herbivore (Helicoverpa punctigera) affects the AM symbiosis in two C4 grass species (Bothriochloa macra and Dichanthium sericeum) and the consequences for host plant growth and nutrient uptake. Aboveground herbivory reduced root growth and carbon allocation belowground in both plant species, along with an associated reduction in arbuscular colonisation and phosphorus uptake. These findings suggest that, in accordance with the carbon-limitation hypothesis, herbivory can suppress the AM symbiosis by decreasing carbon belowground, potentially hindering AM fungal-enhanced nutrient acquisition from the soil.},
	urldate = {2026-03-17},
	journal = {Applied Soil Ecology},
	author = {Frew, Adam},
	month = dec,
	year = {2021},
	keywords = {Arbuscular mycorrhizal fungi, Carbon-limitation hypothesis, Herbivory, Phosphorus, Symbiosis},
	pages = {104133},
}

Most terrestrial plants form associations with arbuscular mycorrhizal (AM) fungi, which are soil-dwelling microbial symbionts that provide plants with soil nutrients, while plants supply the fungi with carbon. The majority of these plants are also subject to herbivory from insects, thus tripartite interactions between insect herbivores, plants, and AM fungi are ubiquitous. This study assessed how aboveground herbivory from a generalist insect herbivore (Helicoverpa punctigera) affects the AM symbiosis in two C4 grass species (Bothriochloa macra and Dichanthium sericeum) and the consequences for host plant growth and nutrient uptake. Aboveground herbivory reduced root growth and carbon allocation belowground in both plant species, along with an associated reduction in arbuscular colonisation and phosphorus uptake. These findings suggest that, in accordance with the carbon-limitation hypothesis, herbivory can suppress the AM symbiosis by decreasing carbon belowground, potentially hindering AM fungal-enhanced nutrient acquisition from the soil.

@article{frew_contrasting_2021,
	title = {Contrasting effects of commercial and native arbuscular mycorrhizal fungal inoculants on plant biomass allocation, nutrients, and phenolics},
	volume = {3},
	copyright = {© 2020 The Author. Plants, People, Planet © New Phytologist Foundation},
	issn = {2572-2611},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/ppp3.10128},
	doi = {10.1002/ppp3.10128},
	abstract = {Societal Impact Statement As the global population increases, the need to feed more people must be met while simultaneously conserving the long-term sustainability of our agroecosystems. There is mounting interest and discussion around the application of arbuscular mycorrhizal fungal (AMF) inoculants to enhance crop growth, nutrient uptake, and pest resistance. However, the effects of AMF inoculation are variable and context dependent. This study found that a multi-species AMF inoculant had a stronger effect on plant biomass allocation and chemistry than a single AMF species inoculant, however, neither of these had a stronger effect than re-inoculating plants with a field-sourced native AMF community.},
	language = {en},
	number = {5},
	urldate = {2026-03-17},
	journal = {PLANTS, PEOPLE, PLANET},
	author = {Frew, Adam},
	year = {2021},
	note = {\_eprint: https://nph.onlinelibrary.wiley.com/doi/pdf/10.1002/ppp3.10128},
	keywords = {arbuscular mycorrhiza, barley, phenolics, phosphorus, sorghum, sustainable agriculture},
	pages = {536--540},
}

Societal Impact Statement As the global population increases, the need to feed more people must be met while simultaneously conserving the long-term sustainability of our agroecosystems. There is mounting interest and discussion around the application of arbuscular mycorrhizal fungal (AMF) inoculants to enhance crop growth, nutrient uptake, and pest resistance. However, the effects of AMF inoculation are variable and context dependent. This study found that a multi-species AMF inoculant had a stronger effect on plant biomass allocation and chemistry than a single AMF species inoculant, however, neither of these had a stronger effect than re-inoculating plants with a field-sourced native AMF community.

@article{frew_different_2021,
	title = {Different mycorrhizal fungal communities differentially affect plant phenolic-based resistance to insect herbivory},
	volume = {19},
	issn = {2452-2198},
	url = {https://www.sciencedirect.com/science/article/pii/S2452219821000616},
	doi = {10.1016/j.rhisph.2021.100365},
	abstract = {Arbuscular mycorrhizal (AM) fungi are ubiquitous symbionts of most terrestrial plants that can augment plant defences against insect herbivores. A clearer understanding of the mechanisms underpinning community-specific effects of AM fungi on plant resistance to herbivores is needed. Here, we report how plant (Triticum aestivum) phenolic-based resistance to an insect herbivore is differentially affected by inoculation with different AM fungal communities. Plants inoculated with four AM fungal species or with a field-sourced AM fungal community had significantly greater foliar phenolics than plants inoculated with a single AM fungal species (Rhizophagus irregularis) or with no AM fungi. Correspondingly, herbivore performance (relative growth rate) was lowest when feeding on those plants with greater phenolic concentrations. Furthermore, there was a negative correlation between foliar phenolics and herbivore growth. We propose that AM fungal community assembly can drive insect herbivore performance by affecting phenolic-based resistance mechanisms.},
	urldate = {2026-03-17},
	journal = {Rhizosphere},
	author = {Frew, Adam and Wilson, Bree A. L.},
	month = sep,
	year = {2021},
	keywords = {Arbuscular mycorrhizal fungi, Herbivory, Multitrophic interactions, Plant defence},
	pages = {100365},
}

Arbuscular mycorrhizal (AM) fungi are ubiquitous symbionts of most terrestrial plants that can augment plant defences against insect herbivores. A clearer understanding of the mechanisms underpinning community-specific effects of AM fungi on plant resistance to herbivores is needed. Here, we report how plant (Triticum aestivum) phenolic-based resistance to an insect herbivore is differentially affected by inoculation with different AM fungal communities. Plants inoculated with four AM fungal species or with a field-sourced AM fungal community had significantly greater foliar phenolics than plants inoculated with a single AM fungal species (Rhizophagus irregularis) or with no AM fungi. Correspondingly, herbivore performance (relative growth rate) was lowest when feeding on those plants with greater phenolic concentrations. Furthermore, there was a negative correlation between foliar phenolics and herbivore growth. We propose that AM fungal community assembly can drive insect herbivore performance by affecting phenolic-based resistance mechanisms.

@article{frew_impacts_2021,
	title = {Impacts of elevated atmospheric {CO2} on arbuscular mycorrhizal fungi and their role in moderating plant allometric partitioning},
	volume = {31},
	issn = {1432-1890},
	url = {https://doi.org/10.1007/s00572-021-01025-6},
	doi = {10.1007/s00572-021-01025-6},
	abstract = {Elevated atmospheric CO2 concentration (eCO2) effects on plants depend on several factors including plant photosynthetic physiology (e.g. C3, C4), soil nutrient availability and plants’ co-evolved soil-dwelling fungal symbionts, namely arbuscular mycorrhizal (AM) fungi. Complicated interactions among these components will determine the outcomes for plants. Therefore, clearer understanding is needed of how plant growth and nutrient uptake, along with root-colonising AM fungal communities, are simultaneously impacted by eCO2. We conducted a factorial growth chamber experiment with a C3 and a C4 grass species (± AM fungi and ± eCO2). We found that eCO2 increased plant biomass allocation towards the roots, but only in plants without AM fungi, potentially associated with an eCO2-driven increase in plant nutrient requirements. Furthermore, our data suggest a difference in the identities of root-colonising fungal taxa between ambient CO2 and eCO2 treatments, particularly in the C4 grass species, although this was not statistically significant. As AM fungi are ubiquitous partners of grasses, their response to increasing atmospheric CO2 is likely to have important consequences for how grassland ecosystems respond to global change.},
	language = {en},
	number = {3},
	urldate = {2026-03-17},
	journal = {Mycorrhiza},
	author = {Frew, Adam and Price, Jodi N. and Oja, Jane and Vasar, Martti and Öpik, Maarja},
	month = may,
	year = {2021},
	keywords = {Allometric partitioning, Arbuscular mycorrhizal fungi, CO2, Grass, Phosphorus, Symbiosis},
	pages = {423--430},
}

Elevated atmospheric CO2 concentration (eCO2) effects on plants depend on several factors including plant photosynthetic physiology (e.g. C3, C4), soil nutrient availability and plants’ co-evolved soil-dwelling fungal symbionts, namely arbuscular mycorrhizal (AM) fungi. Complicated interactions among these components will determine the outcomes for plants. Therefore, clearer understanding is needed of how plant growth and nutrient uptake, along with root-colonising AM fungal communities, are simultaneously impacted by eCO2. We conducted a factorial growth chamber experiment with a C3 and a C4 grass species (± AM fungi and ± eCO2). We found that eCO2 increased plant biomass allocation towards the roots, but only in plants without AM fungi, potentially associated with an eCO2-driven increase in plant nutrient requirements. Furthermore, our data suggest a difference in the identities of root-colonising fungal taxa between ambient CO2 and eCO2 treatments, particularly in the C4 grass species, although this was not statistically significant. As AM fungi are ubiquitous partners of grasses, their response to increasing atmospheric CO2 is likely to have important consequences for how grassland ecosystems respond to global change.

@article{johnson_targeted_2021,
	title = {Targeted plant defense: silicon conserves hormonal defense signaling impacting chewing but not fluid-feeding herbivores},
	volume = {102},
	copyright = {© 2020 by the Ecological Society of America},
	issn = {1939-9170},
	shorttitle = {Targeted plant defense},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/ecy.3250},
	doi = {10.1002/ecy.3250},
	abstract = {Plants deploy an arsenal of chemical and physical defenses against arthropod herbivores, but it may be most cost efficient to produce these only when attacked. Herbivory activates complex signaling pathways involving several phytohormones, including jasmonic acid (JA), which regulate production of defensive compounds. The Poaceae also have the capacity to take up large amounts of silicon (Si), which accumulates in plant tissues. Si accumulation has antiherbivore properties, but it is poorly understood how Si defenses relate to defense hormone signaling. Here we show that Si enrichment causes the model grass Brachypodium distachyon to show lower levels of JA induction when attacked by chewing herbivores. Triggering this hormone even at lower concentrations, however, prompts Si uptake and physical defenses (e.g., leaf hairs), which negatively impact chewing herbivores. Removal of leaf hairs restored performance. Crucially, activation of such Si-based defense is herbivore-specific and occurred only in response to chewing and not fluid-feeding (aphid) herbivores. This aligned with our meta-analysis of 88 studies that showed Si defenses were more effective against chewing herbivores than fluid feeders. Our results suggest integration between herbivore defenses in a model Si-accumulating plant, which potentially allows it to avoid unnecessary activation of other costly defenses.},
	language = {en},
	number = {3},
	urldate = {2026-03-17},
	journal = {Ecology},
	author = {Johnson, Scott N. and Hartley, Susan E. and Ryalls, James M.W. and Frew, Adam and Hall, Casey R.},
	year = {2021},
	note = {\_eprint: https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1002/ecy.3250},
	keywords = {herbivory, insects, jasmonic acid, physical defense, plant defense, silica, silicon},
	pages = {e03250},
}

Plants deploy an arsenal of chemical and physical defenses against arthropod herbivores, but it may be most cost efficient to produce these only when attacked. Herbivory activates complex signaling pathways involving several phytohormones, including jasmonic acid (JA), which regulate production of defensive compounds. The Poaceae also have the capacity to take up large amounts of silicon (Si), which accumulates in plant tissues. Si accumulation has antiherbivore properties, but it is poorly understood how Si defenses relate to defense hormone signaling. Here we show that Si enrichment causes the model grass Brachypodium distachyon to show lower levels of JA induction when attacked by chewing herbivores. Triggering this hormone even at lower concentrations, however, prompts Si uptake and physical defenses (e.g., leaf hairs), which negatively impact chewing herbivores. Removal of leaf hairs restored performance. Crucially, activation of such Si-based defense is herbivore-specific and occurred only in response to chewing and not fluid-feeding (aphid) herbivores. This aligned with our meta-analysis of 88 studies that showed Si defenses were more effective against chewing herbivores than fluid feeders. Our results suggest integration between herbivore defenses in a model Si-accumulating plant, which potentially allows it to avoid unnecessary activation of other costly defenses.

@article{frew_aboveground_2020,
	title = {Aboveground resource allocation in response to root herbivory as affected by the arbuscular mycorrhizal symbiosis},
	volume = {447},
	issn = {1573-5036},
	url = {https://doi.org/10.1007/s11104-019-04399-x},
	doi = {10.1007/s11104-019-04399-x},
	abstract = {Arbuscular mycorrhizal (AM) fungi associate with the majority of terrestrial plants, influencing their growth, nutrient uptake and defence chemistry. Consequently, AM fungi can significantly impact plant-herbivore interactions, yet surprisingly few studies have investigated how AM fungi affect plant responses to root herbivores. This study aimed to investigate how AM fungi affect plant tolerance mechanisms to belowground herbivory.},
	language = {en},
	number = {1},
	urldate = {2026-03-17},
	journal = {Plant and Soil},
	author = {Frew, Adam and Powell, Jeff R. and Johnson, Scott N.},
	month = feb,
	year = {2020},
	keywords = {Arbuscular mycorrhizal fungi, Herbivory, Plant defence, Resource allocation, Tolerance},
	pages = {463--473},
}

Arbuscular mycorrhizal (AM) fungi associate with the majority of terrestrial plants, influencing their growth, nutrient uptake and defence chemistry. Consequently, AM fungi can significantly impact plant-herbivore interactions, yet surprisingly few studies have investigated how AM fungi affect plant responses to root herbivores. This study aimed to investigate how AM fungi affect plant tolerance mechanisms to belowground herbivory.

@article{frew_arbuscular_2019,
	title = {Arbuscular mycorrhizal fungal diversity increases growth and phosphorus uptake in {C3} and {C4} crop plants},
	volume = {135},
	issn = {0038-0717},
	url = {https://www.sciencedirect.com/science/article/pii/S003807171930149X},
	doi = {10.1016/j.soilbio.2019.05.015},
	abstract = {Most plants associate with arbuscular mycorrhizal (AM) fungi which can enhance their growth and nutrient uptake. Outcomes of the AM symbiosis can be highly variable, depending on soil fertility, plant functional group (C3, C4) and AM fungal diversity. This study assessed the growth and nutrient (C, N, P) responses of two C3 (Triticum aestivum and Hordeum vulgare) and two C4 (Sorghum bicolor and Zea mays) plants to different AM fungal inocula (no AM fungi, single AM fungal species, and four AM fungal species) under high and low P conditions. Higher AM fungal diversity resulted in greater P concentration and aboveground biomass of H. vulgare and S. bicolor. Triticum aestivum did not respond to AM fungi, while Z. mays responded positively but a similar positive response of Z. mays growth and nutrition occured when it was colonised with single or multiple AM fungal species. These findings suggest that, although C3 crop plants are less responsive to AM fungi than C4, some C3 and C4 species can benefit from higher AM fungal diversity in the soil.},
	urldate = {2026-03-17},
	journal = {Soil Biology and Biochemistry},
	author = {Frew, Adam},
	month = aug,
	year = {2019},
	keywords = {Arbuscular mycorrhizal fungi, Microbial diversity, Microbial inoculant, Phosphorus nutrition, Plant functional group},
	pages = {248--250},
}

Most plants associate with arbuscular mycorrhizal (AM) fungi which can enhance their growth and nutrient uptake. Outcomes of the AM symbiosis can be highly variable, depending on soil fertility, plant functional group (C3, C4) and AM fungal diversity. This study assessed the growth and nutrient (C, N, P) responses of two C3 (Triticum aestivum and Hordeum vulgare) and two C4 (Sorghum bicolor and Zea mays) plants to different AM fungal inocula (no AM fungi, single AM fungal species, and four AM fungal species) under high and low P conditions. Higher AM fungal diversity resulted in greater P concentration and aboveground biomass of H. vulgare and S. bicolor. Triticum aestivum did not respond to AM fungi, while Z. mays responded positively but a similar positive response of Z. mays growth and nutrition occured when it was colonised with single or multiple AM fungal species. These findings suggest that, although C3 crop plants are less responsive to AM fungi than C4, some C3 and C4 species can benefit from higher AM fungal diversity in the soil.

@article{frew_mycorrhizal-mediated_2019,
	title = {Mycorrhizal-mediated plant–herbivore interactions in a high {CO2} world},
	volume = {33},
	copyright = {© 2019 The Authors. Functional Ecology © 2019 British Ecological Society},
	issn = {1365-2435},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/1365-2435.13347},
	doi = {10.1111/1365-2435.13347},
	abstract = {The symbiotic relationship between terrestrial plants and arbuscular mycorrhizal (AM) fungi is a key driver of plant nutritional and defence traits influencing insect herbivory. These tripartite interactions have been fundamental to shaping the evolution of land plants and the diversity of insect herbivores. Surprisingly, we have little understanding of how these interactions will function under elevated atmospheric CO2 concentrations (eCO2), despite the considerable implications for both natural and managed ecosystems. Although substantial research has revealed how eCO2 alters mycorrhizal–plant interactions, or plant–herbivore interactions, there is a stark scarcity of studies which investigate how eCO2 impacts mycorrhizal-mediated plant–insect herbivore relationships. Here, we synthesise some of the main effects of eCO2 on the mycorrhizal symbiosis, the concomitant impacts on plant nutrient dynamics and secondary metabolism, and how eCO2-driven changes in plant growth, biochemistry and communities impact insect herbivores. We point out that potential mechanistic drivers of AM fungal–plant–insect herbivore relationships under eCO2 can function antagonistically and are highly context-dependent, which poses a particular challenge. Still, we hypothesise as to the potential outcomes for AM fungal–plant–herbivore dynamics under eCO2. We identify key research priorities to tackle the substantial gap in our understanding. If ecological theory is to effectively inform agricultural and natural management practices in the future, research needs to directly investigate how changes in global atmospheric CO2 concentrations impact the tripartite relationship between AM fungi, plants and insect herbivores. A plain language summary is available for this article.},
	language = {en},
	number = {8},
	urldate = {2026-03-17},
	journal = {Functional Ecology},
	author = {Frew, Adam and Price, Jodi N.},
	year = {2019},
	note = {\_eprint: https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2435.13347},
	keywords = {arbuscular mycorrhizal fungi, climate change, elevated atmospheric CO2 concentrations, herbivory, insect},
	pages = {1376--1385},
}

The symbiotic relationship between terrestrial plants and arbuscular mycorrhizal (AM) fungi is a key driver of plant nutritional and defence traits influencing insect herbivory. These tripartite interactions have been fundamental to shaping the evolution of land plants and the diversity of insect herbivores. Surprisingly, we have little understanding of how these interactions will function under elevated atmospheric CO2 concentrations (eCO2), despite the considerable implications for both natural and managed ecosystems. Although substantial research has revealed how eCO2 alters mycorrhizal–plant interactions, or plant–herbivore interactions, there is a stark scarcity of studies which investigate how eCO2 impacts mycorrhizal-mediated plant–insect herbivore relationships. Here, we synthesise some of the main effects of eCO2 on the mycorrhizal symbiosis, the concomitant impacts on plant nutrient dynamics and secondary metabolism, and how eCO2-driven changes in plant growth, biochemistry and communities impact insect herbivores. We point out that potential mechanistic drivers of AM fungal–plant–insect herbivore relationships under eCO2 can function antagonistically and are highly context-dependent, which poses a particular challenge. Still, we hypothesise as to the potential outcomes for AM fungal–plant–herbivore dynamics under eCO2. We identify key research priorities to tackle the substantial gap in our understanding. If ecological theory is to effectively inform agricultural and natural management practices in the future, research needs to directly investigate how changes in global atmospheric CO2 concentrations impact the tripartite relationship between AM fungi, plants and insect herbivores. A plain language summary is available for this article.

@article{frew_silicon_2019,
	title = {Silicon reduces herbivore performance via different mechanisms, depending on host–plant species},
	volume = {44},
	copyright = {© 2019 Ecological Society of Australia},
	issn = {1442-9993},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/aec.12767},
	doi = {10.1111/aec.12767},
	abstract = {There is mounting evidence silicon (Si) can alter plant nutrient dynamics and is an important functional trait in plant defence and plant–insect ecology. Despite this, there remains a paucity in our understanding of how Si-driven changes in nutritional quality can impact herbivore performance across different plant species. We investigated how Si alters plant nutritional quality and the concomitant effects on the performance of the Australian native generalist herbivore Helicoverpa punctigera feeding on three economically significant plant species of varying Si-uptake ability: Brassica napus (non-Si accumulator), Cucumis sativus (intermediate Si accumulator) and Sorghum bicolor (high Si accumulator). Si supplementation reduced the nutritional quality of B. napus but increased phosphorus concentrations in S. bicolor. Si reduced herbivore performance in all host–plant species, which correlated directly with Si concentrations in Si-accumulating host plants C. sativus and S. bicolor. However, on B. napus, Si affected herbivore performance indirectly by reducing nutritional quality (foliar carbon:nitrogen ratio and phosphorus concentration). This suggests Si availability can affect herbivore performance directly via Si concentration on Si-accumulating hosts, and indirectly via nutritional quality in a non-Si accumulator. The resistance-enhancing effects of Si on multiple species offer opportunity for agriculture to utilise this abundant element in sustainable management practices.},
	language = {en},
	number = {6},
	urldate = {2026-03-17},
	journal = {Austral Ecology},
	author = {Frew, Adam and Weston, Leslie A. and Gurr, Geoff M.},
	year = {2019},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/aec.12767},
	keywords = {herbivory, leaf stoichiometry, nutritional quality, plant defence, silicon},
	pages = {1092--1097},
}

There is mounting evidence silicon (Si) can alter plant nutrient dynamics and is an important functional trait in plant defence and plant–insect ecology. Despite this, there remains a paucity in our understanding of how Si-driven changes in nutritional quality can impact herbivore performance across different plant species. We investigated how Si alters plant nutritional quality and the concomitant effects on the performance of the Australian native generalist herbivore Helicoverpa punctigera feeding on three economically significant plant species of varying Si-uptake ability: Brassica napus (non-Si accumulator), Cucumis sativus (intermediate Si accumulator) and Sorghum bicolor (high Si accumulator). Si supplementation reduced the nutritional quality of B. napus but increased phosphorus concentrations in S. bicolor. Si reduced herbivore performance in all host–plant species, which correlated directly with Si concentrations in Si-accumulating host plants C. sativus and S. bicolor. However, on B. napus, Si affected herbivore performance indirectly by reducing nutritional quality (foliar carbon:nitrogen ratio and phosphorus concentration). This suggests Si availability can affect herbivore performance directly via Si concentration on Si-accumulating hosts, and indirectly via nutritional quality in a non-Si accumulator. The resistance-enhancing effects of Si on multiple species offer opportunity for agriculture to utilise this abundant element in sustainable management practices.

@article{johnson_benefits_2018,
	title = {Benefits from {Below}: {Silicon} {Supplementation} {Maintains} {Legume} {Productivity} under {Predicted} {Climate} {Change} {Scenarios}},
	volume = {9},
	issn = {1664-462X},
	shorttitle = {Benefits from {Below}},
	url = {https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2018.00202/full},
	doi = {10.3389/fpls.2018.00202},
	abstract = {Many studies demonstrate that elevated atmospheric carbon dioxide concentrations (eCO2) can promote root nodulation and biological nitrogen fixation (BNF) in legumes such as lucerne (Medicago sativa). But when elevated temperature (eT) conditions are applied in tandem with eCO¬2, a more realistic scenario for future climate change, the positive effects of eCO2 on nodulation and BNF in M. sativa are often much reduced. Silicon (Si) supplementation of M. sativa has also been reported to promote root nodulation and BNF, so could potentially restore the positive effects of eCO2 under eT. Increased nitrogen availability, however, could also increase host suitability for aphid pests, potentially negating any benefit. We applied eCO2 (+240ppm) and eT (+4ºC), separately and in combination, to M. sativa growing in Si supplemented (Si+) and un-supplemented soil (Si-) to determine whether Si moderated the effects of eCO2 and eT. Plants were either inoculated with the aphid Acyrthosiphon pisum or insect-free. In Si- soils, eCO2 stimulated plant growth by 67\% and nodulation by 42\%, respectively, whereas eT reduced these parameters by 26\% and 48\%, respectively. Aphids broadly mirrored these effects on Si- plants, increasing colonization rates under eCO2 and performing much worse (reduced abundance and colonization) under eT when compared to ambient conditions, confirming our hypothesized link between root nodulation, plant growth and pest performance. Examined across all CO2 and temperature regimes, Si supplementation promoted plant growth (+93\%), and root nodulation (+50\%). Acyrthosiphon pisum abundance declined sharply under eT conditions and was largely unaffected by Si supplementation. In conclusion, supplementing M. sativa with Si had consistent positive effects on plant growth and nodulation under different CO2 and temperature scenarios. These findings offer potential for using Si supplementation to maintain legume productivity under predicted climate change scenarios without making legumes more susceptible to insect pests.},
	language = {English},
	urldate = {2026-03-17},
	journal = {Frontiers in Plant Science},
	publisher = {Frontiers},
	author = {Johnson, Scott N. and Ryalls, James M. W. and Gherlenda, Andrew N. and Frew, Adam and Hartley, Susan E.},
	month = feb,
	year = {2018},
	keywords = {Aphids, Atmospheric change, Climate Change, Global Warming, Silicon, alfalfa, silica},
}

Many studies demonstrate that elevated atmospheric carbon dioxide concentrations (eCO2) can promote root nodulation and biological nitrogen fixation (BNF) in legumes such as lucerne (Medicago sativa). But when elevated temperature (eT) conditions are applied in tandem with eCO¬2, a more realistic scenario for future climate change, the positive effects of eCO2 on nodulation and BNF in M. sativa are often much reduced. Silicon (Si) supplementation of M. sativa has also been reported to promote root nodulation and BNF, so could potentially restore the positive effects of eCO2 under eT. Increased nitrogen availability, however, could also increase host suitability for aphid pests, potentially negating any benefit. We applied eCO2 (+240ppm) and eT (+4ºC), separately and in combination, to M. sativa growing in Si supplemented (Si+) and un-supplemented soil (Si-) to determine whether Si moderated the effects of eCO2 and eT. Plants were either inoculated with the aphid Acyrthosiphon pisum or insect-free. In Si- soils, eCO2 stimulated plant growth by 67% and nodulation by 42%, respectively, whereas eT reduced these parameters by 26% and 48%, respectively. Aphids broadly mirrored these effects on Si- plants, increasing colonization rates under eCO2 and performing much worse (reduced abundance and colonization) under eT when compared to ambient conditions, confirming our hypothesized link between root nodulation, plant growth and pest performance. Examined across all CO2 and temperature regimes, Si supplementation promoted plant growth (+93%), and root nodulation (+50%). Acyrthosiphon pisum abundance declined sharply under eT conditions and was largely unaffected by Si supplementation. In conclusion, supplementing M. sativa with Si had consistent positive effects on plant growth and nodulation under different CO2 and temperature scenarios. These findings offer potential for using Si supplementation to maintain legume productivity under predicted climate change scenarios without making legumes more susceptible to insect pests.

@inproceedings{frew_differential_2018,
	title = {Differential impacts of mycorrhizal fungal communities on plant growth and defences drive the performance of invertebrate herbivores: {Ecological} {Society} of {Australia} {Annual} {Conference}},
	shorttitle = {Differential impacts of mycorrhizal fungal communities on plant growth and defences drive the performance of invertebrate herbivores},
	abstract = {Arbuscular mycorrhizal (AM) fungi can be key drivers of soil health, plant productivity, diversity and community structure. Yet the influence of the AM symbiosis reaches far beyond their host plants. More than half of the world’s described insects feed on living plant material. The growth and fitness of these insect herbivores is largely determined by the quality of their host plants, most of which will form associations with AM fungi. Indeed, AM fungi do not only affect the nutrient status of their host, but also impact plant physiology and secondary chemistry which are significant components of plant resistance to herbivory.

Using a variety of glasshouse and controlled environment experiments on sugarcane (Saccharum spp. hybrids) and wheat (Triticum aestivum) we investigated how AM fungal communities impact plant productivity and secondary chemistry, and how this affects invertebrate herbivores. Combining results from these experiments suggests that inoculation with AM fungal communities can either promote or reduce herbivore performance. This is driven by different mycorrhizal-induced changes in plant growth, nutrient status and defence chemistry, which depend on the host plant species.

Considering the ubiquity of mycorrhizal-plant-invertebrate interactions, it is vital that mycorrhizal fungal communities are effectively incorporated into natural resource management strategies within agriculture, restoration and conservation. However, predicting the strength and direction of the effects of AM fungal communities on aspects of plant success and diversity is often challenged by the context specific nature of the outcomes.},
	author = {Frew, Adam},
	month = nov,
	year = {2018},
}

Arbuscular mycorrhizal (AM) fungi can be key drivers of soil health, plant productivity, diversity and community structure. Yet the influence of the AM symbiosis reaches far beyond their host plants. More than half of the world’s described insects feed on living plant material. The growth and fitness of these insect herbivores is largely determined by the quality of their host plants, most of which will form associations with AM fungi. Indeed, AM fungi do not only affect the nutrient status of their host, but also impact plant physiology and secondary chemistry which are significant components of plant resistance to herbivory. Using a variety of glasshouse and controlled environment experiments on sugarcane (Saccharum spp. hybrids) and wheat (Triticum aestivum) we investigated how AM fungal communities impact plant productivity and secondary chemistry, and how this affects invertebrate herbivores. Combining results from these experiments suggests that inoculation with AM fungal communities can either promote or reduce herbivore performance. This is driven by different mycorrhizal-induced changes in plant growth, nutrient status and defence chemistry, which depend on the host plant species. Considering the ubiquity of mycorrhizal-plant-invertebrate interactions, it is vital that mycorrhizal fungal communities are effectively incorporated into natural resource management strategies within agriculture, restoration and conservation. However, predicting the strength and direction of the effects of AM fungal communities on aspects of plant success and diversity is often challenged by the context specific nature of the outcomes.

@article{johnson_dryland_2018,
	title = {Dryland management regimes alter forest habitats and understory arthropod communities},
	volume = {172},
	copyright = {© 2018 Association of Applied Biologists},
	issn = {1744-7348},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/aab.12419},
	doi = {10.1111/aab.12419},
	abstract = {Dryland forests, those characterised as having low precipitation and soil nutrients, account for over a quarter of forests globally. Increasing their productivity often relies on irrigation and fertilisation, but the impacts on the wider habitat are largely unknown. Understory invertebrates, in particular, play key roles in forest systems (e.g. nutrient cycling), but their responses to dryland forest management practices are untested. We investigated the impacts of irrigation, fertilisation and a combination of both on soil chemistry, understory vegetation, tree growth and understory arthropod communities in a Eucalyptus plantation to establish linkages between dryland management and ecosystem responses. Fertilisation increased all soil nutrients (N, NO3N, P and K) with similar effects on the chemical composition of understory grasses. Fertilisation also caused declines in foliar silicon concentrations, an important herbivore defence in grasses. Irrigation increased growth of both understory plants (+90\%) and trees (+68\%). Irrigation increased the abundance of ground-dwelling arthropods by over 480\% relative to control plots, but depressed higher level taxon arthropod diversity by 15\%, declining by a further 7\% (−22\%) in combined treatment plots. Irrigation also caused a surge in the abundance of Collembola (+1300\%) and Isopoda (+323\%). Fertilisation drove increases in the abundance of Isopoda (+196\%) and Diptera (+63\%), whereas fertilisation combined with irrigation increased populations of Thysanoptera (+166\%) and Acarina (+328\%). Airborne arthropods were less affected, but fertilisation increased the abundance of Apocrita (+95\%) and depressed populations of Thysanoptera (−77\%). Diptera abundance was positively related to understory vegetation growth, whereas the abundance of other groups (Collembola, Isopoda, Thysanoptera and Acarina) correlated positively with tree growth. We proposed that the large increases in populations of key detritivores, Collembola and Isopoda, were linked to increased leaf litter from enhanced tree growth in irrigated and combined treatment plots. Our findings suggest that dryland management can increase both plant productivity and abundance of arthropods, but cause arthropod diversity at the higher taxon level to decline overall.},
	language = {en},
	number = {3},
	urldate = {2026-03-17},
	journal = {Annals of Applied Biology},
	author = {Johnson, S.n. and Lopaticki, G. and Aslam, T.j. and Barnett, K. and Frew, A. and Hartley, S.e. and Hiltpold, I. and Nielsen, U.n. and Ryalls, J.m.w.},
	year = {2018},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/aab.12419},
	keywords = {Agroecosystems, arthropods, detritivores, eucalypt, fertilisation, grasses, insects, irrigation, plantation, silicon},
	pages = {282--294},
}

Dryland forests, those characterised as having low precipitation and soil nutrients, account for over a quarter of forests globally. Increasing their productivity often relies on irrigation and fertilisation, but the impacts on the wider habitat are largely unknown. Understory invertebrates, in particular, play key roles in forest systems (e.g. nutrient cycling), but their responses to dryland forest management practices are untested. We investigated the impacts of irrigation, fertilisation and a combination of both on soil chemistry, understory vegetation, tree growth and understory arthropod communities in a Eucalyptus plantation to establish linkages between dryland management and ecosystem responses. Fertilisation increased all soil nutrients (N, NO3N, P and K) with similar effects on the chemical composition of understory grasses. Fertilisation also caused declines in foliar silicon concentrations, an important herbivore defence in grasses. Irrigation increased growth of both understory plants (+90%) and trees (+68%). Irrigation increased the abundance of ground-dwelling arthropods by over 480% relative to control plots, but depressed higher level taxon arthropod diversity by 15%, declining by a further 7% (−22%) in combined treatment plots. Irrigation also caused a surge in the abundance of Collembola (+1300%) and Isopoda (+323%). Fertilisation drove increases in the abundance of Isopoda (+196%) and Diptera (+63%), whereas fertilisation combined with irrigation increased populations of Thysanoptera (+166%) and Acarina (+328%). Airborne arthropods were less affected, but fertilisation increased the abundance of Apocrita (+95%) and depressed populations of Thysanoptera (−77%). Diptera abundance was positively related to understory vegetation growth, whereas the abundance of other groups (Collembola, Isopoda, Thysanoptera and Acarina) correlated positively with tree growth. We proposed that the large increases in populations of key detritivores, Collembola and Isopoda, were linked to increased leaf litter from enhanced tree growth in irrigated and combined treatment plots. Our findings suggest that dryland management can increase both plant productivity and abundance of arthropods, but cause arthropod diversity at the higher taxon level to decline overall.

@incollection{frew_fraaije_2018,
	title = {Fraaije, {BA}, 355 {Frahm}, {CS}, 346 {Freitas}, {SS}, 309},
	volume = {172, 3},
	issn = {0003-4746, 1744-7348},
	booktitle = {Annals of applied biology: an international journal of the {AAB}},
	author = {Frew, Adam},
	year = {2018},
	pages = {392},
}

@article{frew_mycorrhizal_2018,
	title = {Mycorrhizal fungi enhance nutrient uptake but disarm defences in plant roots, promoting plant-parasitic nematode populations},
	volume = {126},
	issn = {0038-0717},
	url = {https://www.sciencedirect.com/science/article/pii/S003807171830275X},
	doi = {10.1016/j.soilbio.2018.08.019},
	abstract = {Arbuscular mycorrhizal (AM) fungi are ubiquitous components of the soil biota which live symbiotically with terrestrial plants. Plant-parasitic nematodes are an important group of soil-dwelling invertebrates that inflict considerable damage to crops, representing a serious threat to food security. The effects of the AM symbiosis on plant-parasitic nematodes can be variable, and the mechanisms driving such variability remain ambiguous. We tested the impacts of inoculation with AM fungi on the root metabolic profile and nutritional chemistry of two varieties of wheat (Triticum aestivum), and how this affected populations of the plant-parasitic nematode Pratylenchus neglectus. AM fungi reduced plant biomass by almost 24\%, yet increased root concentrations of phosphorus, potassium and zinc by 50\%, 15\% and 16\%, respectively. Contrary to our predictions, nematode populations were 47–117\% higher on AM inoculated plants, depending on variety. Untargeted metabolomic profiling revealed significant effects of mycorrhizal colonisation on certain markers of biological interest, these compounds were the benzoxazinoid glucoside defence compounds DIBOA-Glc, HMBOA-Glc and HDMBOA-Glc. Overall, mycorrhizae reduced abundances of these defence metabolites, which were potentially driving AM fungi – nematode interactions; although for DIBOA-Glc this was dependent on wheat variety. Moreover, there was a negative correlation between total AM colonisation and DIBOA-Glc concentrations. Our results demonstrate AM fungi can reduce plant biomass and supress root defence compounds associated with plant resistance to invertebrate pests, while still providing nutritional benefit to the host plant. This highlights that mycorrhizal colonisation of wheat varieties can have simultaneous positive and negative effects on different plant traits which drive plant-herbivore interactions. In working towards effective exploitation of the AM symbiosis in sustainable plant production, the context dependent outcomes of mycorrhizal-plant-nematode interactions is a key challenge. Untargeted metabolomic profiling offers the ability to reveal some of the driving mechanisms underpinning such complex tripartite interactions in the soil.},
	urldate = {2026-03-17},
	journal = {Soil Biology and Biochemistry},
	author = {Frew, Adam and Powell, Jeff R. and Glauser, Gaétan and Bennett, Alison E. and Johnson, Scott N.},
	month = nov,
	year = {2018},
	keywords = {Below-ground, Benzoxazinoids, Defence, Growth, Metabolomics, Mycorrhiza, Plant defence},
	pages = {123--132},
}

Arbuscular mycorrhizal (AM) fungi are ubiquitous components of the soil biota which live symbiotically with terrestrial plants. Plant-parasitic nematodes are an important group of soil-dwelling invertebrates that inflict considerable damage to crops, representing a serious threat to food security. The effects of the AM symbiosis on plant-parasitic nematodes can be variable, and the mechanisms driving such variability remain ambiguous. We tested the impacts of inoculation with AM fungi on the root metabolic profile and nutritional chemistry of two varieties of wheat (Triticum aestivum), and how this affected populations of the plant-parasitic nematode Pratylenchus neglectus. AM fungi reduced plant biomass by almost 24%, yet increased root concentrations of phosphorus, potassium and zinc by 50%, 15% and 16%, respectively. Contrary to our predictions, nematode populations were 47–117% higher on AM inoculated plants, depending on variety. Untargeted metabolomic profiling revealed significant effects of mycorrhizal colonisation on certain markers of biological interest, these compounds were the benzoxazinoid glucoside defence compounds DIBOA-Glc, HMBOA-Glc and HDMBOA-Glc. Overall, mycorrhizae reduced abundances of these defence metabolites, which were potentially driving AM fungi – nematode interactions; although for DIBOA-Glc this was dependent on wheat variety. Moreover, there was a negative correlation between total AM colonisation and DIBOA-Glc concentrations. Our results demonstrate AM fungi can reduce plant biomass and supress root defence compounds associated with plant resistance to invertebrate pests, while still providing nutritional benefit to the host plant. This highlights that mycorrhizal colonisation of wheat varieties can have simultaneous positive and negative effects on different plant traits which drive plant-herbivore interactions. In working towards effective exploitation of the AM symbiosis in sustainable plant production, the context dependent outcomes of mycorrhizal-plant-nematode interactions is a key challenge. Untargeted metabolomic profiling offers the ability to reveal some of the driving mechanisms underpinning such complex tripartite interactions in the soil.

@article{frew_role_2018,
	title = {The role of silicon in plant biology: a paradigm shift in research approach},
	volume = {121},
	issn = {0305-7364},
	shorttitle = {The role of silicon in plant biology},
	url = {https://pmc.ncbi.nlm.nih.gov/articles/PMC6007437/},
	doi = {10.1093/aob/mcy009},
	abstract = {Background
Silicon (Si) is known to have numerous beneficial effects on plants, alleviating diverse forms of abiotic and biotic stress. Research on this topic has accelerated in recent years and revealed multiple effects of Si in a range of plant species. Available information regarding the impact of Si on plant defence, growth and development is fragmented, discipline-specific, and usually focused on downstream, distal phenomena rather than underlying effects. Accordingly, there is a growing need for studies that address fundamental metabolic and regulatory processes, thereby allowing greater unification and focus of current research across disciplines.

Scope and Conclusions
Silicon is often regarded as a plant nutritional ‘non-entity’. A suite of factors associated with Si have been recently identified, relating to plant chemistry, physiology, gene regulation and interactions with other organisms. Research to date has typically focused on the impact of Si application upon plant stress responses. However, the fundamental, underlying mechanisms that account for the manifold effects of Si in plant biology remain undefined. Here, the known effects of Si in higher plants relating to alleviation of both abiotic and biotic stress are briefly reviewed and the potential importance of Si in plant primary metabolism is discussed, highlighting the need for a unifying research framework targeting common underlying mechanisms. The traditional approach of discipline-specific work on single stressors in individual plant species is currently inadequate. Thus, a holistic and comparative approach is proposed to assess the mode of action of Si between plant trait types (e.g. C3, C4 and CAM; Si accumulators and non-accumulators) and between biotic and abiotic stressors (pathogens, herbivores, drought, salt), considering potential pathways (i.e. primary metabolic processes) highlighted by recent empirical evidence. Utilizing genomic, transcriptomic, proteomic and metabolomic approaches in such comparative studies will pave the way for unification of the field and a deeper understanding of the role of Si in plants.},
	number = {7},
	urldate = {2026-03-17},
	journal = {Annals of Botany},
	author = {Frew, Adam and Weston, Leslie A and Reynolds, Olivia L and Gurr, Geoff M},
	month = jun,
	year = {2018},
	pages = {1265--1273},
}

Background Silicon (Si) is known to have numerous beneficial effects on plants, alleviating diverse forms of abiotic and biotic stress. Research on this topic has accelerated in recent years and revealed multiple effects of Si in a range of plant species. Available information regarding the impact of Si on plant defence, growth and development is fragmented, discipline-specific, and usually focused on downstream, distal phenomena rather than underlying effects. Accordingly, there is a growing need for studies that address fundamental metabolic and regulatory processes, thereby allowing greater unification and focus of current research across disciplines. Scope and Conclusions Silicon is often regarded as a plant nutritional ‘non-entity’. A suite of factors associated with Si have been recently identified, relating to plant chemistry, physiology, gene regulation and interactions with other organisms. Research to date has typically focused on the impact of Si application upon plant stress responses. However, the fundamental, underlying mechanisms that account for the manifold effects of Si in plant biology remain undefined. Here, the known effects of Si in higher plants relating to alleviation of both abiotic and biotic stress are briefly reviewed and the potential importance of Si in plant primary metabolism is discussed, highlighting the need for a unifying research framework targeting common underlying mechanisms. The traditional approach of discipline-specific work on single stressors in individual plant species is currently inadequate. Thus, a holistic and comparative approach is proposed to assess the mode of action of Si between plant trait types (e.g. C3, C4 and CAM; Si accumulators and non-accumulators) and between biotic and abiotic stressors (pathogens, herbivores, drought, salt), considering potential pathways (i.e. primary metabolic processes) highlighted by recent empirical evidence. Utilizing genomic, transcriptomic, proteomic and metabolomic approaches in such comparative studies will pave the way for unification of the field and a deeper understanding of the role of Si in plants.

@article{frew_arbuscular_2017,
	title = {Arbuscular mycorrhizal fungi promote silicon accumulation in plant roots, reducing the impacts of root herbivory},
	volume = {419},
	issn = {1573-5036},
	url = {https://doi.org/10.1007/s11104-017-3357-z},
	doi = {10.1007/s11104-017-3357-z},
	abstract = {Studies have shown that arbuscular mycorrhizal (AM) fungi can reduce the performance of typically detrimental root feeding insects, yet the mechanisms remain unclear. This study aimed to investigate the effects of different sources of AM inocula on plant resistance to a root feeding insect in two different soils with different silicon (Si) concentrations.},
	language = {en},
	number = {1},
	urldate = {2026-03-18},
	journal = {Plant and Soil},
	author = {Frew, Adam and Powell, Jeff R. and Allsopp, Peter G. and Sallam, Nader and Johnson, Scott N.},
	month = oct,
	year = {2017},
	keywords = {Arbuscular mycorrhizal fungi, Insect herbivory, Root defences, Silicon, Sugarcane},
	pages = {423--433},
}

Studies have shown that arbuscular mycorrhizal (AM) fungi can reduce the performance of typically detrimental root feeding insects, yet the mechanisms remain unclear. This study aimed to investigate the effects of different sources of AM inocula on plant resistance to a root feeding insect in two different soils with different silicon (Si) concentrations.

@inproceedings{frew_arbuscular_2017,
	title = {Arbuscular mycorrhizal fungi reduce canegrub performance via multiple mechanisms including increased silicon concentrations: 39th {Annual} {Conference} of the {Australian} {Society} of {Sugar} {Cane} {Technologists}},
	shorttitle = {Arbuscular mycorrhizal fungi reduce canegrub performance via multiple mechanisms including increased silicon concentrations},
	url = {https://assct.com.au/conference/past-conferences/112-2017-assct-conference},
	abstract = {As below ground herbivores and arbuscular mycorrhizal (AM) fungi share the soil environment, there is potentially strong selection pressure for AM fungi to support plant defences against root herbivores. AM fungi negatively impact root feeding insects, yet the mechanisms remain unknown. Plant silicon (Si) is an effective defence against root feeding insects, and AM fungi have been observed to increase Si in plants. This highlights the potential role of Si within defences against root herbivores mediated by AM fungi.  
We grew sugarcane (Saccharum spp. hybrids) in high and low Si soils, associated with native AM fungal communities, a commercial AM fungal community or with no AM fungi. Canegrub (Dermolepida albohirtum) performance was measured in a feeding assay.
Within low Si soil, both commercial and native AM communities reduced canegrub growth rates by 107 and 81\%, respectively, while increasing root Si concentrations by 70\% and 41\%, respectively. Within high Si soil, AM fungi had no impact on plant Si concentrations or canegrub growth.
Our evidence suggests the negative impacts of AM fungi on root herbivores are associated with an increase in plant Si, when soil Si is limited. The results also highlight that AM fungi can impact root herbivores through other mechanisms independent of Si, therefore further research is required to better understand this complex interaction.},
	urldate = {2026-03-17},
	author = {Frew, Adam and Powell, Jeff R. and Allsopp, Peter G. and Sallam, Nader and Johnson, Scott N.},
	year = {2017},
	keywords = {Arbuscular Mycorrhizal Fungi, Canegrub,, Plant Defences, Root Herbivory, Silicon},
	pages = {213--216},
}

As below ground herbivores and arbuscular mycorrhizal (AM) fungi share the soil environment, there is potentially strong selection pressure for AM fungi to support plant defences against root herbivores. AM fungi negatively impact root feeding insects, yet the mechanisms remain unknown. Plant silicon (Si) is an effective defence against root feeding insects, and AM fungi have been observed to increase Si in plants. This highlights the potential role of Si within defences against root herbivores mediated by AM fungi. We grew sugarcane (Saccharum spp. hybrids) in high and low Si soils, associated with native AM fungal communities, a commercial AM fungal community or with no AM fungi. Canegrub (Dermolepida albohirtum) performance was measured in a feeding assay. Within low Si soil, both commercial and native AM communities reduced canegrub growth rates by 107 and 81%, respectively, while increasing root Si concentrations by 70% and 41%, respectively. Within high Si soil, AM fungi had no impact on plant Si concentrations or canegrub growth. Our evidence suggests the negative impacts of AM fungi on root herbivores are associated with an increase in plant Si, when soil Si is limited. The results also highlight that AM fungi can impact root herbivores through other mechanisms independent of Si, therefore further research is required to better understand this complex interaction.

@article{frew_host_2017,
	title = {Host plant colonisation by arbuscular mycorrhizal fungi stimulates immune function whereas high root silicon concentrations diminish growth in a soil-dwelling herbivore},
	volume = {112},
	issn = {0038-0717},
	url = {https://www.sciencedirect.com/science/article/pii/S0038071717303139},
	doi = {10.1016/j.soilbio.2017.05.008},
	abstract = {Plant nutritional quality is dependent on soil nutrients and co-evolved soil microbial symbionts. Most plants associate with arbuscular mycorrhizal (AM) fungi, which alter their nutritional quality and silicon (Si) uptake from the soil. High Si concentrations reduce plant nutritional quality and can act as an effective defence both aboveground and belowground. The growth and immune function of insect herbivores is dependent on the quality of their host plants, hence the AM symbiosis and Si concentrations can impact insect growth and immunity via changes in host plant quality. The effects of AM fungi or Si on root herbivores are poorly quantified, while impacts on insect immunity are unknown. We investigated the effects of host plant colonisation by AM fungi and high root Si concentrations on plant quality alongside the growth of a root feeding insect and the immune response to entomopathogenic nematode infection. Two sugarcane varieties (Saccharum species hybrids L.) were grown under fully factorial treatment combinations of ± Si and AM/non-AM. Root feeding insects (Dermolepida albohirtum Waterhouse) fed on the plants and their immune function was assessed in a bioassay, while insect growth and root consumption were assessed in a feeding trial. We found high Si concentrations decreased insect growth and root consumption, the latter by 71\%. Insect growth was reduced on plants associated with AM fungi, which was dependent on Si treatment and plant variety. Insect immunity increased by 62\% on AM colonised plants, which negatively correlated with insect growth. These results demonstrate that the impacts of the AM symbiosis on root feeding insects can depend on Si availability and plant variety. Our study suggests that AM fungi can prime insect immunity, independent of host plant quality or Si concentrations, and the negative effects of AM fungi on soil dwelling insects involves immune function stimulation which, due to a growth-immunity trade-off, results in growth reduction.},
	urldate = {2026-03-17},
	journal = {Soil Biology and Biochemistry},
	author = {Frew, Adam and Powell, Jeff R. and Hiltpold, Ivan and Allsopp, Peter G. and Sallam, Nader and Johnson, Scott N.},
	month = sep,
	year = {2017},
	keywords = {Arbuscular mycorrhizal fungi, Belowground herbivory, Entomopathogenic nematodes, Immune priming, Plant quality, Silicon},
	pages = {117--126},
}

Plant nutritional quality is dependent on soil nutrients and co-evolved soil microbial symbionts. Most plants associate with arbuscular mycorrhizal (AM) fungi, which alter their nutritional quality and silicon (Si) uptake from the soil. High Si concentrations reduce plant nutritional quality and can act as an effective defence both aboveground and belowground. The growth and immune function of insect herbivores is dependent on the quality of their host plants, hence the AM symbiosis and Si concentrations can impact insect growth and immunity via changes in host plant quality. The effects of AM fungi or Si on root herbivores are poorly quantified, while impacts on insect immunity are unknown. We investigated the effects of host plant colonisation by AM fungi and high root Si concentrations on plant quality alongside the growth of a root feeding insect and the immune response to entomopathogenic nematode infection. Two sugarcane varieties (Saccharum species hybrids L.) were grown under fully factorial treatment combinations of ± Si and AM/non-AM. Root feeding insects (Dermolepida albohirtum Waterhouse) fed on the plants and their immune function was assessed in a bioassay, while insect growth and root consumption were assessed in a feeding trial. We found high Si concentrations decreased insect growth and root consumption, the latter by 71%. Insect growth was reduced on plants associated with AM fungi, which was dependent on Si treatment and plant variety. Insect immunity increased by 62% on AM colonised plants, which negatively correlated with insect growth. These results demonstrate that the impacts of the AM symbiosis on root feeding insects can depend on Si availability and plant variety. Our study suggests that AM fungi can prime insect immunity, independent of host plant quality or Si concentrations, and the negative effects of AM fungi on soil dwelling insects involves immune function stimulation which, due to a growth-immunity trade-off, results in growth reduction.

@article{frew_increased_2017,
	title = {Increased root herbivory under elevated atmospheric carbon dioxide concentrations is reversed by silicon-based plant defences},
	volume = {54},
	copyright = {© 2016 The Authors. Journal of Applied Ecology © 2016 British Ecological Society},
	issn = {1365-2664},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/1365-2664.12822},
	doi = {10.1111/1365-2664.12822},
	abstract = {Predicted increases in atmospheric concentrations of CO2 may alter the susceptibility of many plants to insect herbivores due to changes in plant nutrition and defences. Silicon plays a critical role in plant defence against herbivores, so increasing such silicon-based defences in plants may help remediate situations where plants become more susceptible to herbivores. Sugar cane (Saccharum spp. hybrid) was subjected to fully factorial treatment combinations of ambient (aCO2) or elevated (eCO2) atmospheric CO2 concentrations; ambient silicon or silicon supplementation; insect-free or subject to root herbivory by greyback canegrub (Dermolepida albohirtum). A glasshouse study was used to determine how these factors affected rates of photosynthesis, growth, chemistry (concentrations of silicon, carbon, nitrogen and non-structural carbohydrates). Changes in canegrub mass were determined in the glasshouse pot study, together with more detailed assessment of how eCO2 and silicon supplementation affected performance and feeding behaviour (relative growth rate and relative consumption) in a 24-h feeding efficiency assay. Elevated CO2 and silicon supplementation increased rates of photosynthesis (+32\% and 14\%, respectively) and sugar cane biomass (+45\% and 69\%, respectively). Silicon supplementation increased silicon concentrations in both leaves and roots by 54\% and 75\%, respectively. eCO2 caused root C : N to increase by 12\%. Canegrub performance and consumption increased under eCO2; relative growth rate (RGR) increased by 116\% and consumed 57\% more root material (suggestive of compensatory feeding). Silicon application reversed these effects, with large decreases in mass change, RGR and root consumption (65\% less root mass consumed). Synthesis and applications. Our results suggest future atmospheric carbon dioxide concentrations could lead to increased crop damage by a below-ground herbivore. Increasing bioavailable silicon in soil stimulated silicon-based defences which dramatically decreased herbivory and herbivore performance. Our findings suggest future pest management strategies could benefit from characterising deficiencies in bioavailable silicon in agricultural soils and targeted application of silicon fertilisers. Moreover, future breeding programmes should exploit variation in silicon uptake between cultivars to enhance silicon uptake in new crop varieties. Silicon-based plant defence proved to be highly beneficial for remediating the negative effects of atmospheric change on sugar cane susceptibility to herbivory and could be applicable in other crops.},
	language = {en},
	number = {5},
	urldate = {2026-03-17},
	journal = {Journal of Applied Ecology},
	author = {Frew, Adam and Allsopp, Peter G. and Gherlenda, Andrew N. and Johnson, Scott N.},
	year = {2017},
	note = {\_eprint: https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2664.12822},
	keywords = {atmospheric concentrations of CO2, below-ground herbivory, climate change, crop damage, insect herbivore, pest management, plant defences, silicon, sugar cane},
	pages = {1310--1319},
}

Predicted increases in atmospheric concentrations of CO2 may alter the susceptibility of many plants to insect herbivores due to changes in plant nutrition and defences. Silicon plays a critical role in plant defence against herbivores, so increasing such silicon-based defences in plants may help remediate situations where plants become more susceptible to herbivores. Sugar cane (Saccharum spp. hybrid) was subjected to fully factorial treatment combinations of ambient (aCO2) or elevated (eCO2) atmospheric CO2 concentrations; ambient silicon or silicon supplementation; insect-free or subject to root herbivory by greyback canegrub (Dermolepida albohirtum). A glasshouse study was used to determine how these factors affected rates of photosynthesis, growth, chemistry (concentrations of silicon, carbon, nitrogen and non-structural carbohydrates). Changes in canegrub mass were determined in the glasshouse pot study, together with more detailed assessment of how eCO2 and silicon supplementation affected performance and feeding behaviour (relative growth rate and relative consumption) in a 24-h feeding efficiency assay. Elevated CO2 and silicon supplementation increased rates of photosynthesis (+32% and 14%, respectively) and sugar cane biomass (+45% and 69%, respectively). Silicon supplementation increased silicon concentrations in both leaves and roots by 54% and 75%, respectively. eCO2 caused root C : N to increase by 12%. Canegrub performance and consumption increased under eCO2; relative growth rate (RGR) increased by 116% and consumed 57% more root material (suggestive of compensatory feeding). Silicon application reversed these effects, with large decreases in mass change, RGR and root consumption (65% less root mass consumed). Synthesis and applications. Our results suggest future atmospheric carbon dioxide concentrations could lead to increased crop damage by a below-ground herbivore. Increasing bioavailable silicon in soil stimulated silicon-based defences which dramatically decreased herbivory and herbivore performance. Our findings suggest future pest management strategies could benefit from characterising deficiencies in bioavailable silicon in agricultural soils and targeted application of silicon fertilisers. Moreover, future breeding programmes should exploit variation in silicon uptake between cultivars to enhance silicon uptake in new crop varieties. Silicon-based plant defence proved to be highly beneficial for remediating the negative effects of atmospheric change on sugar cane susceptibility to herbivory and could be applicable in other crops.

@article{johnson_silicon-induced_2017,
	title = {Silicon-induced root nodulation and synthesis of essential amino acids in a legume is associated with higher herbivore abundance},
	volume = {31},
	copyright = {© 2017 The Authors. Functional Ecology © 2017 British Ecological Society},
	issn = {1365-2435},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/1365-2435.12893},
	doi = {10.1111/1365-2435.12893},
	abstract = {Ecologists have become increasingly aware that silicon uptake by plants, especially the Poaceae, can have beneficial effects on both plant growth and herbivore defence. The effects of silicon on other plant functional groups, such as nitrogen-fixing legumes, have been less well studied. Silicon could, however, indirectly promote herbivore performance in this group if reported increases in N2 fixation caused improvements in host plant quality for herbivores. We tested how silicon supplementation in the legume (Medicago sativa) affected plant growth rates, root nodulation and foliage quality (silicon content and amino acid profiles) for an insect herbivore (Acyrthosiphon pisum). Plants supplemented with silicon (Si+) grew three times as quickly as those without supplementation (Si−), almost entirely in shoot mass. While root growth was unaffected by silicon uptake, root nodules containing nitrogen-fixing bacteria were 44\% more abundant on Si+ plants. Aphid abundance was twice as high on Si+ plants compared to Si− plants and was positively correlated with silicon-stimulated plant growth. Si+ plants accumulated more than twice as much silicon as Si− plants, but did not have higher silicon concentrations because of dilution effects linked to the rapid growth of Si+ plants. Si+ plants showed a 65\% increase in synthesis of essential foliar amino acids, probably due to increased levels of root nodulation. These results suggest that increased silicon supply makes M. sativa more susceptible to A. pisum, mainly because of increased plant growth and resource availability (i.e. essential amino acids). While silicon augmentation of the Poaceae frequently improves herbivore defence, the current study illustrates that this cannot be assumed for other plant families where the beneficial effects of silicon on plant growth and nutrition may promote herbivore performance in some instances. A lay summary is available for this article.},
	language = {en},
	number = {10},
	urldate = {2026-03-17},
	journal = {Functional Ecology},
	author = {Johnson, Scott N. and Hartley, Susan E. and Ryalls, James M. W. and Frew, Adam and DeGabriel, Jane L. and Duncan, Michael and Gherlenda, Andrew N.},
	year = {2017},
	note = {\_eprint: https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2435.12893},
	keywords = {amino acids, aphids, legume, nitrogen fixation, nodulation, plant defence, silica, silicon},
	pages = {1903--1909},
}

Ecologists have become increasingly aware that silicon uptake by plants, especially the Poaceae, can have beneficial effects on both plant growth and herbivore defence. The effects of silicon on other plant functional groups, such as nitrogen-fixing legumes, have been less well studied. Silicon could, however, indirectly promote herbivore performance in this group if reported increases in N2 fixation caused improvements in host plant quality for herbivores. We tested how silicon supplementation in the legume (Medicago sativa) affected plant growth rates, root nodulation and foliage quality (silicon content and amino acid profiles) for an insect herbivore (Acyrthosiphon pisum). Plants supplemented with silicon (Si+) grew three times as quickly as those without supplementation (Si−), almost entirely in shoot mass. While root growth was unaffected by silicon uptake, root nodules containing nitrogen-fixing bacteria were 44% more abundant on Si+ plants. Aphid abundance was twice as high on Si+ plants compared to Si− plants and was positively correlated with silicon-stimulated plant growth. Si+ plants accumulated more than twice as much silicon as Si− plants, but did not have higher silicon concentrations because of dilution effects linked to the rapid growth of Si+ plants. Si+ plants showed a 65% increase in synthesis of essential foliar amino acids, probably due to increased levels of root nodulation. These results suggest that increased silicon supply makes M. sativa more susceptible to A. pisum, mainly because of increased plant growth and resource availability (i.e. essential amino acids). While silicon augmentation of the Poaceae frequently improves herbivore defence, the current study illustrates that this cannot be assumed for other plant families where the beneficial effects of silicon on plant growth and nutrition may promote herbivore performance in some instances. A lay summary is available for this article.

@article{frew_comparison_2016,
	title = {A comparison of canefield soil types on root herbivore performance and feeding},
	shorttitle = {A {Comparison} of {Canefield} {Soil} {Tyoes} on {Root} {Herbivore} {Performance} and {Feeding}},
	url = {https://scholar.archive.org/work/fhtyytcokbfm3pikysaxtsiuf4/access/wayback/https://s3-eu-west-1.amazonaws.com/pfigshare-u-files/8259296/Frew_Johnson_2017_188190.pdf},
	abstract = {Soil nutrients and quality are important factors, not only for plant growth but also for belowground herbivore performance (Barnett and Johnson, 2013; Erb and Lu, 2013), and can be a driving factor for grassland communities (Russell, 1973). Indeed, for many managed grassland and grass crop systems, the application of nutrient fertilisers is common practice to ensure maximum growth and yield. However, fertilisers are often applied without any characterisation of base soil nutrient concentrations or availability. Therefore, fertiliser application could often be unnecessary and can potentially be both economically and ecologically damaging (Stevens et al., 2004; Tilman, 1999).},
	journal = {Invertebrate ecology in Australasian grasslands.},
	publisher = {Proceedings of the Ninth ACGIE},
	author = {Frew, Adam and Johnson, Scott N.},
	year = {2016},
	pages = {188--190},
}

Soil nutrients and quality are important factors, not only for plant growth but also for belowground herbivore performance (Barnett and Johnson, 2013; Erb and Lu, 2013), and can be a driving factor for grassland communities (Russell, 1973). Indeed, for many managed grassland and grass crop systems, the application of nutrient fertilisers is common practice to ensure maximum growth and yield. However, fertilisers are often applied without any characterisation of base soil nutrient concentrations or availability. Therefore, fertiliser application could often be unnecessary and can potentially be both economically and ecologically damaging (Stevens et al., 2004; Tilman, 1999).

@article{frew_belowground_2016,
	title = {Belowground {Ecology} of {Scarabs} {Feeding} on {Grass} {Roots}: {Current} {Knowledge} and {Future} {Directions} for {Management} in {Australasia}},
	volume = {7},
	issn = {1664-462X},
	shorttitle = {Belowground {Ecology} of {Scarabs} {Feeding} on {Grass} {Roots}},
	url = {https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2016.00321/full},
	doi = {10.3389/fpls.2016.00321},
	abstract = {Many scarab beetles spend the majority of their lives belowground as larvae, feeding on grass roots. Many of these larvae are significant pests, causing damage to crops and grasslands. Damage by larvae of the greyback cane beetle (Dermolepida albohirtum), for example, can cause financial losses of up to AU\$40 million annually to the Australian sugarcane industry. We review the ecology of some scarab larvae in Australasia, focusing on three subfamilies; Dynastinae, Rutelinae and Melolonthinae, containing key pest species. Although considerable research on the control of some scarab pests has been carried out in Australasia, for some species, the basic biology and ecology remains largely unexplored. We synthesize what is known about these scarab larvae and outline key knowledge gaps to highlights future research directions with a view to improve pest management. We do this by presenting an overview of the scarab larval host plants and feeding behavior; the impacts of abiotic (temperature, moisture and fertilization) and biotic (pathogens, natural enemies and microbial symbionts) factors on scarab larvae and conclude with how abiotic and biotic factors can be applied in agriculture for improved pest management, suggesting future research directions.Several host plant microbial symbionts, such as arbuscular mycorrhizal fungi and endophytes, can improve plant tolerance to scarabs and reduce larval performance, which have shown promise for use in pest management. In addition to this, several microbial scarab pathogens have been isolated for commercial use in pest management with particularly promising results. The entomopathogenic fungus Metarhizium anisopliae caused a 50\% reduction in cane beetle larvae while natural enemies such as entomopathogenic nematodes have also shown potential as a biocontrol. Continued research should focus on filling the gaps in the knowledge of the basic ecology and feeding behavior of scarab larval species within Australasia. This should include host plant preferences and behavioral cues which could be utilized in pest management, for example, in trap crops. The direction of future research in biocontrol strategies should focus on identifying naturally occurring, locally adapted pathogens, if they are to achieve high efficacy in the field.},
	language = {English},
	urldate = {2026-03-17},
	journal = {Frontiers in Plant Science},
	publisher = {Frontiers},
	author = {Frew, Adam and Barnett, Kirk and Nielsen, Uffe N. and Riegler, Markus and Johnson, Scott N.},
	month = mar,
	year = {2016},
	keywords = {Anoplognathus, Belowground herbivory, Cyclocephala signaticollis, Dermolepida albohirtum, Heteronychus arator, Sericesthis nigrolineata, pasture, pest management},
}

Many scarab beetles spend the majority of their lives belowground as larvae, feeding on grass roots. Many of these larvae are significant pests, causing damage to crops and grasslands. Damage by larvae of the greyback cane beetle (Dermolepida albohirtum), for example, can cause financial losses of up to AU$40 million annually to the Australian sugarcane industry. We review the ecology of some scarab larvae in Australasia, focusing on three subfamilies; Dynastinae, Rutelinae and Melolonthinae, containing key pest species. Although considerable research on the control of some scarab pests has been carried out in Australasia, for some species, the basic biology and ecology remains largely unexplored. We synthesize what is known about these scarab larvae and outline key knowledge gaps to highlights future research directions with a view to improve pest management. We do this by presenting an overview of the scarab larval host plants and feeding behavior; the impacts of abiotic (temperature, moisture and fertilization) and biotic (pathogens, natural enemies and microbial symbionts) factors on scarab larvae and conclude with how abiotic and biotic factors can be applied in agriculture for improved pest management, suggesting future research directions.Several host plant microbial symbionts, such as arbuscular mycorrhizal fungi and endophytes, can improve plant tolerance to scarabs and reduce larval performance, which have shown promise for use in pest management. In addition to this, several microbial scarab pathogens have been isolated for commercial use in pest management with particularly promising results. The entomopathogenic fungus Metarhizium anisopliae caused a 50% reduction in cane beetle larvae while natural enemies such as entomopathogenic nematodes have also shown potential as a biocontrol. Continued research should focus on filling the gaps in the knowledge of the basic ecology and feeding behavior of scarab larval species within Australasia. This should include host plant preferences and behavioral cues which could be utilized in pest management, for example, in trap crops. The direction of future research in biocontrol strategies should focus on identifying naturally occurring, locally adapted pathogens, if they are to achieve high efficacy in the field.

@article{johnson_new_2016,
	title = {New frontiers in belowground ecology for plant protection from root-feeding insects},
	volume = {108},
	issn = {0929-1393},
	url = {https://www.sciencedirect.com/science/article/pii/S0929139316302116},
	doi = {10.1016/j.apsoil.2016.07.017},
	abstract = {Herbivorous insect pests living in the soil represent a significant challenge to food security given their persistence, the acute damage they cause to plants and the difficulties associated with managing their populations. Ecological research effort into rhizosphere interactions has increased dramatically in the last decade and we are beginning to understand, in particular, the ecology of how plants defend themselves against soil-dwelling pests. In this review, we synthesise information about four key ecological mechanisms occurring in the rhizosphere or surrounding soil that confer plant protection against root herbivores. We focus on root tolerance, root resistance via direct physical and chemical defences, particularly via acquisition of silicon-based plant defences, integration of plant mutualists (microbes and entomopathogenic nematodes, EPNs) and the influence of soil history and feedbacks. Their suitability as management tools, current limitations for their application, and the opportunities for development are evaluated. We identify opportunities for synergy between these aspects of rhizosphere ecology, such as mycorrhizal fungi negatively affecting pests at the root-interface but also increasing plant uptake of silicon, which is also known to reduce herbivory. Finally, we set out research priorities for developing potential novel management strategies.},
	urldate = {2026-03-17},
	journal = {Applied Soil Ecology},
	author = {Johnson, Scott N. and Benefer, Carly M. and Frew, Adam and Griffiths, Bryan S. and Hartley, Susan E. and Karley, Alison J. and Rasmann, Sergio and Schumann, Mario and Sonnemann, Illja and Robert, Christelle A. M.},
	month = dec,
	year = {2016},
	keywords = {Belowground herbivores, Ecological applications, Rhizosphere, Root herbivory, Root-feeding insects, Soils},
	pages = {96--107},
}

Herbivorous insect pests living in the soil represent a significant challenge to food security given their persistence, the acute damage they cause to plants and the difficulties associated with managing their populations. Ecological research effort into rhizosphere interactions has increased dramatically in the last decade and we are beginning to understand, in particular, the ecology of how plants defend themselves against soil-dwelling pests. In this review, we synthesise information about four key ecological mechanisms occurring in the rhizosphere or surrounding soil that confer plant protection against root herbivores. We focus on root tolerance, root resistance via direct physical and chemical defences, particularly via acquisition of silicon-based plant defences, integration of plant mutualists (microbes and entomopathogenic nematodes, EPNs) and the influence of soil history and feedbacks. Their suitability as management tools, current limitations for their application, and the opportunities for development are evaluated. We identify opportunities for synergy between these aspects of rhizosphere ecology, such as mycorrhizal fungi negatively affecting pests at the root-interface but also increasing plant uptake of silicon, which is also known to reduce herbivory. Finally, we set out research priorities for developing potential novel management strategies.

@article{johnson_importance_2016,
	title = {The {Importance} of {Testing} {Multiple} {Environmental} {Factors} in {Legume}–{Insect} {Research}: {Replication}, {Reviewers}, and {Rebuttal}},
	volume = {7},
	issn = {1664-462X},
	shorttitle = {The {Importance} of {Testing} {Multiple} {Environmental} {Factors} in {Legume}–{Insect} {Research}},
	url = {https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2016.00489/full},
	doi = {10.3389/fpls.2016.00489},
	abstract = {The case for testing multiple environmental factorsInvestigating the impacts of predicted changes in our atmosphere and climate change on insect-plant interactions is a widely pursued area of research. To date, the majority of experimental studies have tested the impacts of single environmental factors on insect-plant interactions, but meta-analyses have clearly illustrated the importance of investigating multiple factors in tandem (Zvereva and Kozlov, 2006; Robinson et al., 2012). In particular, environmental change factors often interact with each other which can either strengthen or mitigate the effects of environmental factors acting alone (Robinson et al., 2012). For example, the positive effects of elevated atmospheric carbon dioxide concentrations (e[CO2]) on plant growth are stronger under high nitrogen (N) conditions compared to low N conditions (+32\% and +19\%, respectively) (Robinson et al., 2012). Likewise, from the limited number of studies available, Robinson et al. (2012) showed that e[CO2] had different impacts on plant nitrogen, plant biomass and secondary metabolites under elevated air temperature (eT) conditions. This does not invalidate single factor studies, of which we have published numerous examples, but this is an important consideration for making realistic predictions about how plants and insects will respond to future climates (Facey et al., 2014).Legume-insect interactionsA key feature of legumes is their capacity for biological nitrogen fixation (BNF), which they accomplish via symbiotic relationships with soil bacteria which associate with the plant in discrete root nodules. Given that insect herbivores are frequently nitrogen limited (Mattson, 1980), concentrations of N in legumes derived from BNF are likely to be crucial determinants of plant-herbivore interactions. Legumes differ markedly from non-legume plants in their responses to environmental change because BNF is often significantly affected (Robinson et al., 2012). Moreover, e[CO2] and eT appear to have contrasting effects on BNF; e[CO2] tends to promote BNF via several mechanisms (Soussana and Hartwig, 1996), including larger numbers of N2-fixing symbiotic bacteria in the rhizosphere (Schortemeyer et al., 1996), increased nodulation (Ryle and Powell, 1992) and enhanced nitrogenase activity (Norby, 1987). In contrast, eT tends to have an inhibitory effect on BNF because of the low tolerance of N2-fixing bacteria to higher temperatures (Zahran, 1999; Whittington et al., 2013). These generalisations are, of course, contingent on nutrient availability in the soil (e.g. Edwards et al., 2006).Given this, one might assume that e[CO2] and eT might have contrasting impacts on insect herbivores of legumes since they affect nitrogen concentrations in the plant tissues in a divergent manner. This seems to be the case, with e[CO2] either having no adverse effects (e.g. Karowe and Migliaccio, 2011) or, more often, a beneficial impact on herbivore performance (e.g. Johnson and McNicol, 2010), particularly for aphids (Guo et al., 2013a; 2013b; Johnson et al., 2014). However, our recent work with lucerne (Medicago sativa) has shown that the positive impacts of e[CO2] on pea aphids (Acyrthosiphon pisum) were negated under eT because eT caused decreases in nodulation and amino acid concentrations in the foliage (Ryalls et al., 2013; Ryalls et al., 2014). Testing multiple environmental factors, including soil nutrients, therefore seems to be particularly relevant for investigations into how legume herbivores will respond to atmospheric and climate change research. The challenges: replication and reviewersWhy are there so few multi-factorial experiments in climate change research? Put simply, constraints on replication are the biggest obstacles faced by investigators. Pseudoreplication (a term first coined in Hurlbert, 1984) is particularly common in climate change research (Newman et al., 2011). For example, 49 of the 110 climate change studies reviewed by Wernberg et al. (2012) had pseudoreplication issues. This usually arises because when environmental factors are applied to controlled chambers, glasshouses or FACE (Free Air CO2 Enrichment) rings, the unit of replication for those treatments is the chamber, greenhouse, or ring, respectively (Lindroth and Raffa, 2016). Subunits (e.g. individual plants) are not independently subjected to the treatment, and therefore not true replicates. As a result, statistical tests are based on artificially high degrees of freedom, resulting in a larger F statistic, potentially leading to type I errors (i.e. false positives) (Lindroth and Raffa, 2016). For this reason, many reviewers for scientific journals automatically reject manuscripts if any part of an experiment is pseudoreplicated without necessarily considering whether the biological conclusions of the study are really compromised by pseudoreplication (Davies and Gray, 2015). This is possibly an overzealous interpretation of the case by Hurlbert (1984), the authority on the subject, who states that ‘there should be no automatic rejection of [such] experiments’ (Hurlbert, 2004). In a recent and comprehensive article, Davies and Gray argue convincingly that reviewers erroneously and dogmatically reject papers that have pseudoreplication issues which is slowing the pact of ecological research. While Davies and Gray (2015) focussed on non-manipulative experiments in natural systems, many of the points were germane to multi-factorial climate change research. In particular, many contemporary statistical tests, such as nested designs and random/mixed effect models, account for the lack of independence between pseudoreplicates so may help in some cases (Fernando Chaves, 2010; Leather et al., 2014; Davies and Gray, 2015). Of course, such statistical approaches could only help where a treatment combination was repeated in more than one chamber, glasshouse or FACE ring. Comparing experimental approaches – potential for rebuttal?How do researchers attempt to overcome the pseudoreplication problem experimentally? The simplest way is to avoid it altogether by fully replicating environmental treatments. However, using even the bare minimum of replicates (e.g. N = 4) would require 16 separate chambers, glasshouses or rings for an e[CO2] x eT experiment. Many researchers cannot readily access this number of identical facilities or monopolise them for that matter. Repeating the experiment several times and using experimental run as the source of replication is another approach (e.g. Johnson et al., 2011), but this can be logistically demanding in time and cost. Even when fully replicated, the degrees of freedom in these studies are often so low that they are susceptible to type II errors, whereby ‘real responses’ are not statistically detected (e.g. the ‘false negative’). Another approach that researchers sometimes use is ‘chamber swapping’, whereby experimental units (e.g. plants) are moved within, and then between, chambers with attendant changes in environmental conditions (e.g. Bezemer et al., 1998). This does not eliminate pseudoreplication, but rather serves to minimise its effects by equalising any unintended ‘chamber effects’ across all experimental units. While this approach might be criticised because chamber effects might affect plants differently during different stages of their development (Potvin and Tardif, 1988), researchers have addressed this by staggering experiments so plants are exposed to particular chambers at the same stage of development (e.g. Vuorinen et al., 2004a; 2004b).How do results from a ‘chamber swapping’ experiment compare with replicated experiments? We can answer this question, in part, using three comparable published studies that examined the impacts of environmental change on interactions between lucerne and the pea aphid. One experiment was replicated using multiple chambers (Johnson et al., 2014), one replicated using multiple experimental runs (Ryalls et al., 2014) and one adopted the chamber swapping approach (Ryalls, 2016). The first of these only examined e[CO2], whereas the other two experiments also included eT. Figure 1 shows the increase in dry mass of plants (with and without aphids) grown under e[CO2] and eT relative to plants grown under ambient conditions. This response was selected for comparison since it was evidently measured the same way in each experiment. Despite using very different approaches, in most cases we obtained very similar responses whether the experiment was fully replicated or conducted with regular chamber swaps (c. every 10 days). This is a crude comparison, but it is reassuring that we obtained similar data and reached identical conclusions using the chamber swapping approach. Conclusions and RecommendationsWhile incorporation of multiple environmental factors is desirable in many climate change studies of plant-herbivore interactions (clearly advocated by Robinson et al., 2012), we argue here that it is especially relevant to legume-insect research. Nitrogen status in legumes is shaped by BNF, which is highly affected by atmospheric and climatic change, often in divergent directions. This will inevitably affect legume quality for herbivores (i.e. especially primary metabolites, but possibly secondary metabolites too), and likely affect herbivore abundance and performance. Nonetheless, experimental manipulation of multiple factors is challenging and prone to pseudoreplication. ‘Chamber swapping’ does not eliminate this problem, but it appears to minimise ‘chamber effects’ and give comparable results to fully replicated experiments – at least in the lucerne-aphid system. We recommend that researchers working in other systems also take a cautious approach with regard to careful replication until they can develop confidence that their observed effects are real and repeatable. The statistical significance of numerical differences remain inflated, however, so it would be judicious to treat any marginally significant results with caution and rather interpret effect sizes rather than P values per se (see discussion by Ellison et al., 2014). Davies and Gray (2015) make the similar arguments and suggest that conclusions can be phrased as new hypotheses if necessary. In conclusion, we agree with Newman et al. (2011) on this issue that ‘as long as authors are clear about the use of pseudoreplicates, and the readers appreciate the potential problems interpreting such results, then such studies are valuable despite their pseudoreplication’.},
	language = {English},
	urldate = {2026-03-17},
	journal = {Frontiers in Plant Science},
	publisher = {Frontiers},
	author = {Johnson, Scott N. and Gherlenda, Andrew N. and Frew, Adam and Ryalls, James M. W.},
	month = apr,
	year = {2016},
	keywords = {Atmospheric change, Climate Change, biological nitrogen fixation, insect-plant interactions, legumes, pastures.},
}

The case for testing multiple environmental factorsInvestigating the impacts of predicted changes in our atmosphere and climate change on insect-plant interactions is a widely pursued area of research. To date, the majority of experimental studies have tested the impacts of single environmental factors on insect-plant interactions, but meta-analyses have clearly illustrated the importance of investigating multiple factors in tandem (Zvereva and Kozlov, 2006; Robinson et al., 2012). In particular, environmental change factors often interact with each other which can either strengthen or mitigate the effects of environmental factors acting alone (Robinson et al., 2012). For example, the positive effects of elevated atmospheric carbon dioxide concentrations (e[CO2]) on plant growth are stronger under high nitrogen (N) conditions compared to low N conditions (+32% and +19%, respectively) (Robinson et al., 2012). Likewise, from the limited number of studies available, Robinson et al. (2012) showed that e[CO2] had different impacts on plant nitrogen, plant biomass and secondary metabolites under elevated air temperature (eT) conditions. This does not invalidate single factor studies, of which we have published numerous examples, but this is an important consideration for making realistic predictions about how plants and insects will respond to future climates (Facey et al., 2014).Legume-insect interactionsA key feature of legumes is their capacity for biological nitrogen fixation (BNF), which they accomplish via symbiotic relationships with soil bacteria which associate with the plant in discrete root nodules. Given that insect herbivores are frequently nitrogen limited (Mattson, 1980), concentrations of N in legumes derived from BNF are likely to be crucial determinants of plant-herbivore interactions. Legumes differ markedly from non-legume plants in their responses to environmental change because BNF is often significantly affected (Robinson et al., 2012). Moreover, e[CO2] and eT appear to have contrasting effects on BNF; e[CO2] tends to promote BNF via several mechanisms (Soussana and Hartwig, 1996), including larger numbers of N2-fixing symbiotic bacteria in the rhizosphere (Schortemeyer et al., 1996), increased nodulation (Ryle and Powell, 1992) and enhanced nitrogenase activity (Norby, 1987). In contrast, eT tends to have an inhibitory effect on BNF because of the low tolerance of N2-fixing bacteria to higher temperatures (Zahran, 1999; Whittington et al., 2013). These generalisations are, of course, contingent on nutrient availability in the soil (e.g. Edwards et al., 2006).Given this, one might assume that e[CO2] and eT might have contrasting impacts on insect herbivores of legumes since they affect nitrogen concentrations in the plant tissues in a divergent manner. This seems to be the case, with e[CO2] either having no adverse effects (e.g. Karowe and Migliaccio, 2011) or, more often, a beneficial impact on herbivore performance (e.g. Johnson and McNicol, 2010), particularly for aphids (Guo et al., 2013a; 2013b; Johnson et al., 2014). However, our recent work with lucerne (Medicago sativa) has shown that the positive impacts of e[CO2] on pea aphids (Acyrthosiphon pisum) were negated under eT because eT caused decreases in nodulation and amino acid concentrations in the foliage (Ryalls et al., 2013; Ryalls et al., 2014). Testing multiple environmental factors, including soil nutrients, therefore seems to be particularly relevant for investigations into how legume herbivores will respond to atmospheric and climate change research. The challenges: replication and reviewersWhy are there so few multi-factorial experiments in climate change research? Put simply, constraints on replication are the biggest obstacles faced by investigators. Pseudoreplication (a term first coined in Hurlbert, 1984) is particularly common in climate change research (Newman et al., 2011). For example, 49 of the 110 climate change studies reviewed by Wernberg et al. (2012) had pseudoreplication issues. This usually arises because when environmental factors are applied to controlled chambers, glasshouses or FACE (Free Air CO2 Enrichment) rings, the unit of replication for those treatments is the chamber, greenhouse, or ring, respectively (Lindroth and Raffa, 2016). Subunits (e.g. individual plants) are not independently subjected to the treatment, and therefore not true replicates. As a result, statistical tests are based on artificially high degrees of freedom, resulting in a larger F statistic, potentially leading to type I errors (i.e. false positives) (Lindroth and Raffa, 2016). For this reason, many reviewers for scientific journals automatically reject manuscripts if any part of an experiment is pseudoreplicated without necessarily considering whether the biological conclusions of the study are really compromised by pseudoreplication (Davies and Gray, 2015). This is possibly an overzealous interpretation of the case by Hurlbert (1984), the authority on the subject, who states that ‘there should be no automatic rejection of [such] experiments’ (Hurlbert, 2004). In a recent and comprehensive article, Davies and Gray argue convincingly that reviewers erroneously and dogmatically reject papers that have pseudoreplication issues which is slowing the pact of ecological research. While Davies and Gray (2015) focussed on non-manipulative experiments in natural systems, many of the points were germane to multi-factorial climate change research. In particular, many contemporary statistical tests, such as nested designs and random/mixed effect models, account for the lack of independence between pseudoreplicates so may help in some cases (Fernando Chaves, 2010; Leather et al., 2014; Davies and Gray, 2015). Of course, such statistical approaches could only help where a treatment combination was repeated in more than one chamber, glasshouse or FACE ring. Comparing experimental approaches – potential for rebuttal?How do researchers attempt to overcome the pseudoreplication problem experimentally? The simplest way is to avoid it altogether by fully replicating environmental treatments. However, using even the bare minimum of replicates (e.g. N = 4) would require 16 separate chambers, glasshouses or rings for an e[CO2] x eT experiment. Many researchers cannot readily access this number of identical facilities or monopolise them for that matter. Repeating the experiment several times and using experimental run as the source of replication is another approach (e.g. Johnson et al., 2011), but this can be logistically demanding in time and cost. Even when fully replicated, the degrees of freedom in these studies are often so low that they are susceptible to type II errors, whereby ‘real responses’ are not statistically detected (e.g. the ‘false negative’). Another approach that researchers sometimes use is ‘chamber swapping’, whereby experimental units (e.g. plants) are moved within, and then between, chambers with attendant changes in environmental conditions (e.g. Bezemer et al., 1998). This does not eliminate pseudoreplication, but rather serves to minimise its effects by equalising any unintended ‘chamber effects’ across all experimental units. While this approach might be criticised because chamber effects might affect plants differently during different stages of their development (Potvin and Tardif, 1988), researchers have addressed this by staggering experiments so plants are exposed to particular chambers at the same stage of development (e.g. Vuorinen et al., 2004a; 2004b).How do results from a ‘chamber swapping’ experiment compare with replicated experiments? We can answer this question, in part, using three comparable published studies that examined the impacts of environmental change on interactions between lucerne and the pea aphid. One experiment was replicated using multiple chambers (Johnson et al., 2014), one replicated using multiple experimental runs (Ryalls et al., 2014) and one adopted the chamber swapping approach (Ryalls, 2016). The first of these only examined e[CO2], whereas the other two experiments also included eT. Figure 1 shows the increase in dry mass of plants (with and without aphids) grown under e[CO2] and eT relative to plants grown under ambient conditions. This response was selected for comparison since it was evidently measured the same way in each experiment. Despite using very different approaches, in most cases we obtained very similar responses whether the experiment was fully replicated or conducted with regular chamber swaps (c. every 10 days). This is a crude comparison, but it is reassuring that we obtained similar data and reached identical conclusions using the chamber swapping approach. Conclusions and RecommendationsWhile incorporation of multiple environmental factors is desirable in many climate change studies of plant-herbivore interactions (clearly advocated by Robinson et al., 2012), we argue here that it is especially relevant to legume-insect research. Nitrogen status in legumes is shaped by BNF, which is highly affected by atmospheric and climatic change, often in divergent directions. This will inevitably affect legume quality for herbivores (i.e. especially primary metabolites, but possibly secondary metabolites too), and likely affect herbivore abundance and performance. Nonetheless, experimental manipulation of multiple factors is challenging and prone to pseudoreplication. ‘Chamber swapping’ does not eliminate this problem, but it appears to minimise ‘chamber effects’ and give comparable results to fully replicated experiments – at least in the lucerne-aphid system. We recommend that researchers working in other systems also take a cautious approach with regard to careful replication until they can develop confidence that their observed effects are real and repeatable. The statistical significance of numerical differences remain inflated, however, so it would be judicious to treat any marginally significant results with caution and rather interpret effect sizes rather than P values per se (see discussion by Ellison et al., 2014). Davies and Gray (2015) make the similar arguments and suggest that conclusions can be phrased as new hypotheses if necessary. In conclusion, we agree with Newman et al. (2011) on this issue that ‘as long as authors are clear about the use of pseudoreplicates, and the readers appreciate the potential problems interpreting such results, then such studies are valuable despite their pseudoreplication’.

@article{frew_trade-offs_2016,
	title = {Trade-{Offs} between {Silicon} and {Phenolic} {Defenses} may {Explain} {Enhanced} {Performance} of {Root} {Herbivores} on {Phenolic}-{Rich} {Plants}},
	volume = {42},
	issn = {1573-1561},
	url = {https://doi.org/10.1007/s10886-016-0734-7},
	doi = {10.1007/s10886-016-0734-7},
	abstract = {Phenolic compounds play a role in plant defense against herbivores. For some herbivorous insects, particularly root herbivores, host plants with high phenolic concentrations promote insect performance and tissue consumption. This positive relationship between some insects and phenolics, however, could reflect a negative correlation with other plant defenses acting against insects. Silicon is an important element for plant growth and defense, particularly in grasses, as many grass species take up large amounts of silicon. Negative impact of a high silicon diet on insect herbivore performance has been reported aboveground, but is unreported for belowground herbivores. It has been hypothesized that some silicon accumulating plants exhibit a trade-off between carbon-based defense compounds, such as phenolics, and silicon-based defenses. Here, we investigated the impact of silicon concentrations and total phenolic concentrations in sugarcane roots on the performance of the root-feeding greyback canegrub (Dermolepida albohirtum). Canegrub performance was positively correlated with root phenolics, but negatively correlated with root silicon. We found a negative relationship in the roots between total phenolics and silicon concentrations. This suggests the positive impact of phenolic compounds on some insects may be the effect of lower concentrations of silicon compounds in plant tissue. This is the first demonstration of plant silicon negatively affecting a belowground herbivore.},
	language = {en},
	number = {8},
	urldate = {2026-03-17},
	journal = {Journal of Chemical Ecology},
	author = {Frew, Adam and Powell, Jeff R. and Sallam, Nader and Allsopp, Peter G. and Johnson, Scott N.},
	month = aug,
	year = {2016},
	keywords = {Carbon, Insect herbivory, Phenolics, Silicon, Sugarcane, Trade-off},
	pages = {768--771},
}

Phenolic compounds play a role in plant defense against herbivores. For some herbivorous insects, particularly root herbivores, host plants with high phenolic concentrations promote insect performance and tissue consumption. This positive relationship between some insects and phenolics, however, could reflect a negative correlation with other plant defenses acting against insects. Silicon is an important element for plant growth and defense, particularly in grasses, as many grass species take up large amounts of silicon. Negative impact of a high silicon diet on insect herbivore performance has been reported aboveground, but is unreported for belowground herbivores. It has been hypothesized that some silicon accumulating plants exhibit a trade-off between carbon-based defense compounds, such as phenolics, and silicon-based defenses. Here, we investigated the impact of silicon concentrations and total phenolic concentrations in sugarcane roots on the performance of the root-feeding greyback canegrub (Dermolepida albohirtum). Canegrub performance was positively correlated with root phenolics, but negatively correlated with root silicon. We found a negative relationship in the roots between total phenolics and silicon concentrations. This suggests the positive impact of phenolic compounds on some insects may be the effect of lower concentrations of silicon compounds in plant tissue. This is the first demonstration of plant silicon negatively affecting a belowground herbivore.

@article{frew_eucalypt_2013,
	title = {Do eucalypt plantation management practices create understory reservoirs of scarab beetle pests in the soil?},
	volume = {306},
	issn = {0378-1127},
	url = {https://www.sciencedirect.com/science/article/pii/S0378112713004192},
	doi = {10.1016/j.foreco.2013.06.051},
	abstract = {Eucalypt management practices can affect the population dynamics of defoliating insects. To date, research has focused on how these practices alter eucalypt physiology and chemistry, which in turn affect canopy herbivores. Management practices such as irrigation and fertilisation, however, could also shape the understory plant community and potentially improve habitats for grass root-feeding scarab beetle larvae that later can become defoliators as adults. Using a large scale factorial field experiment comprising 2560 Eucalyptus saligna, we investigated the effects of irrigation and fertilisation on the understory ecology of a eucalypt plantation. We specifically focussed on grass communities and populations of scarab beetles and their natural enemies (entomopathogenic nematodes, EPNs). Irrigation and fertilisation increased grass coverage by 40\% and 42\%, respectively, and affected grass species composition. In particular, fertilisation favoured colonisation with C3 grasses (e.g. Microlaena stipoides) that have higher nitrogen concentrations over lower quality C4 grasses (e.g. Setaria incrassata). Fertilisation increased the nitrogen concentration of grasses by 30\% on average. Scarab abundance increased by 52\% in fertilised plots, potentially due to higher nutritional quality of host plants and the dominance of nutritionally superior species. Irrigation increased soil water content, but did not promote scarab larvae abundance. The presence of EPNs, however, was 78\% higher in irrigated plots, which suggests scarab larvae populations may have been controlled by EPNs. This study illustrates how plantation management practices can affect understory communities of both plants and soil invertebrates with potential for creating ‘reservoirs’ of scarab beetle pests.},
	urldate = {2026-03-17},
	journal = {Forest Ecology and Management},
	author = {Frew, Adam and Nielsen, Uffe N. and Riegler, Markus and Johnson, Scott N.},
	month = oct,
	year = {2013},
	keywords = {Fertilisation, Grass understory, Irrigation, Nematodes, Root herbivores},
	pages = {275--280},
}

Eucalypt management practices can affect the population dynamics of defoliating insects. To date, research has focused on how these practices alter eucalypt physiology and chemistry, which in turn affect canopy herbivores. Management practices such as irrigation and fertilisation, however, could also shape the understory plant community and potentially improve habitats for grass root-feeding scarab beetle larvae that later can become defoliators as adults. Using a large scale factorial field experiment comprising 2560 Eucalyptus saligna, we investigated the effects of irrigation and fertilisation on the understory ecology of a eucalypt plantation. We specifically focussed on grass communities and populations of scarab beetles and their natural enemies (entomopathogenic nematodes, EPNs). Irrigation and fertilisation increased grass coverage by 40% and 42%, respectively, and affected grass species composition. In particular, fertilisation favoured colonisation with C3 grasses (e.g. Microlaena stipoides) that have higher nitrogen concentrations over lower quality C4 grasses (e.g. Setaria incrassata). Fertilisation increased the nitrogen concentration of grasses by 30% on average. Scarab abundance increased by 52% in fertilised plots, potentially due to higher nutritional quality of host plants and the dominance of nutritionally superior species. Irrigation increased soil water content, but did not promote scarab larvae abundance. The presence of EPNs, however, was 78% higher in irrigated plots, which suggests scarab larvae populations may have been controlled by EPNs. This study illustrates how plantation management practices can affect understory communities of both plants and soil invertebrates with potential for creating ‘reservoirs’ of scarab beetle pests.