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Karin Ljung received on Saturday the Roséns Linnaeus Prize in Botany (Photo: Fredrik Larsson)
Last Saturday, Karin Ljung was presented the Roséns Linnaeus Prize in Botany from the Royal Physiographic Society of Lund. She is awarded for her research efforts investigating root development and root-to-shoot communication in plants. Karin Ljung is sharing the prize with Jon Ågren from Uppsala University.
Karin Ljung’s research primarily focuses on plant growth and development. She investigates how plant hormones, which are small substances regulating plant growth, control the formation of roots and coordinate the communication between plant tissues above and below ground. Together with her group, she has developed analytical methods to measure plant hormones in various tissues and cells, and recently even in different compartments within a cell.
“I feel very honoured receiving this prize, says Karin Ljung. “Research is a group effort, and I especially would like to thank my group members for their contribution and Umeå Plant Science Centre for providing an excellent research environment.”
After establishing her group at Umeå Plant Science Centre in 2005, Karin Ljung became a professor at SLU in 2015. She has published more than 160 papers, many of which have been highly cited. Since 2014, she has consistently appeared on the Clarivate Analytics list of Highly Cited Researchers. Earlier recognitions for her contributions to plant research include the OlChemIm Award, the SPPS Prize given by the Scandinavian Plant Physiology Society, and earlier this year, the Arvid Lindman medal from SLU.
The Roséns Linnaeus Prizes in Botany and Zoology have been presented every third year since 1935. The recipients are Swedish researchers deemed highly deserving by the Royal Physiographic Society of Lund. This year’s prizes were handed over at the society’s annual meeting in Lund on December 2nd.
More information
The Royal Physiographic Society of Lund
Medals and prizes awarded by the Royal Physiographic Society of Lund
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PhD student Pierrick Bru is measuring how much light energy is converted into heat in Arabidopsis thaliana plants. Photo: Alexis Brun
Just like people can get sunburned, plants can also suffer from too much sunlight. To stay healthy, they use an internal “sun protection mechanism”. Pierrick Bru, a PhD student working with Alizée Malnoë at Umeå Plant Science Centre and Umeå University, has been studying a special component of this plant "sun protection mechanism" called qH and found it is quite adaptable.
The magic of photosynthetic organisms is that they can produce energy from sunlight. Plants have tiny structures in their cells, that, similarly to mini solar panels, catch sunlight and turn it into energy-rich compounds which the plant is then utilizing to grow and stay healthy. However, when there is too much light, these structures can get overloaded and damaged. To prevent this from occuring, plants use a photoprotection mechanism known as non-photochemical quenching, which converts excess sunlight into heat, allowing it to dissipate harmlessly.
“qH is one of the components of this non-photochemical quenching system and it is the component that we focussed on in our research,” explains Pierrick Bru. “This component does not work quickly. It takes hours to turn on and off, and it is mainly active when plants are under prolonged excess of light stress, especially when combined with other environmental cues such as cold and/or drought.”
To understand more about qH, Pierrick and his colleagues did experiments with the plant model organism Arabidopsis thaliana. They modified the plant by removing one or more of the mini solar panels and found that the plant has a backup system: if one panel is missing, the others can compensate for it. However, when a particular small panel, known as Lhcb6, is not there, qH could not work properly and less of the excess sunlight was turned into heat.
The researchers did not stop here but went on to investigate further how this photoprotection mechanism works and to search for other missing actors that regulate the qH mechanism. They introduced random changes in the genome of Arabidopsis thaliana, where the plant’s blueprint is stored, and looked for modified plants that had issues with their sunlight protection. Out of 22,000 plants screened, they found 150 with altered protection mechanisms. They took a closer look at 61 of them and identified about eighteen new actors that could be involved in the qH mechanism.
Two of these actors are involved in building or repairing photosystem II – one of the two functional units where photosynthesis takes place. If either of the two actors found did not work well, photosystem II could not function as usual, and this caused problems also for the plants to use the qH sun protection mechanism.
Pierrick Bru and his colleagues do not know yet how exactly the defects of photosystem II impact the qH protection mechanism. They will continue investigating this in the model organism Arabidopsis thaliana, where it is easy and fast to make new discoveries. This understanding will open doors to investigate if photoprotection qH is regulated similarly in crops.
“Crops are suffering already now from more extreme weather conditions caused by climate change. This will affect our capacity to grow healthy crops and good food for an increasing population,” explains Pierrick Bru. “Understanding how qH works and how plants cope with environmental stress will help to find ways to improve plant resistance to excess of sunlight, improving plant growth and increase agriculture productivity.”
About the public defence
Pierrick Bru, Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, defends his PhD thesis with the title “Investigating the molecular mechanism of photoprotection qH, in Arabidopis thaliana” on Friday, 8th of December 2023. Faculty opponent is Stefano Caffarri, Department of Biology, Aix-Marseille University, Marseille, France. The thesis was supervised by Alizée Malnoë.
Link to Pierrick Bru's PhD thesis
For more information, please contact:
Pierrick Bru
Umeå Plant Science Centre
Department of Plant Physiology
Umeå University
Email:
Text: Pierrick Bru, Anne Honsel
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At the field site in Wuhan, China: Young aspen trees (in front) keep their leaves longer than older trees (in the back). Photo taken on November 23, 2023 by Kejing Wang.
In a forest, even trees have their generational conflicts. Young trees often find themselves under the canopy of the older trees. Their survival strategy is to kick off their growth earlier in spring and stay longer green in autumn. A research team from Umeå Plant Science Centre, SLU, and Huazhong Agricultural University in China has revealed that a small RNA molecule acts as a master regulator in aspen, modulating the length of the growing season in an age dependent manner.
The study was published this week in the journal Proceedings of the National Academy of Sciences (PNAS).
It takes time for a young tree in a forest to grow tall enough to escape the shading of the surrounding adult generation. To establish themselves, young trees employ a risky strategy: they extend their growing season to capture light before and after being fully shaded by the older trees. This phenomenon was observed earlier but it was not clear how trees adjust the length of their growing season based on age.
“Initially, we did not aim to study growth cessation but rather the role of a short RNA molecule – microRNA156 – known to control plant maturation,” explains Ove Nilsson, professor at SLU and group leader at Umeå Plant Science Centre. “These microRNAs bind to RNAs of other genes to degrade them or inhibit their activity.”
When the research groups of Ove Nilsson and Jihua Ding, a former postdoc in Ove Nilsson’s group, investigated how hybrid aspen trees responded to an increased activity of microRNA156, they observed that the trees stopped their growth and set their buds later than control trees. The researchers grew the plants under greenhouse conditions and simulated seasonal changes by adjusting temperature and day length. Under these conditions, the modified trees also opened their buds earlier.
“We did not expect this behaviour and got intrigued to study it further,” adds Jihua Ding who is now leading a research group at Huazhong Agricultural University in Wuhan, China. “We studied the literature and realized that several papers describe findings that juvenile forest trees often extend their growing season compared to older trees in the same forest. However, the underlying mechanisms were not yet understood.”
The researchers focused on the seasonal growth stop in autumn and analysed the molecular changes accompanying the increased activity of microRNA156. The activity of several genes known to control the timing of bud set in the fall was strongly affected in the modified trees. It turned out that microRNA156 acts as a master regulator during growth cessation through the so-called SPL genes and the central seasonal growth regulator FT2, connecting tree maturation and the regulation of seasonal growth regulation.
“The regulation mechanism that we discovered in aspen is different than what was previously described in the model plant Arabidopsis,” says Ove Nilsson. “Perennial trees have evolved different survival strategies than annual plants, and it is obvious that these strategies are regulated differently dependent on the age of the tree. When we better understand the underlying mechanisms of these strategies, we can gain a clearer understanding of how trees adapt to a changing environment and climate change.”
The article
Xiaoli Liao, Yunjie Su, Maria Klintenäs, Yue Li, Shashank Sane, Zhihao Wu, Qihui Chen, Bo Zhang, Ove Nilsson and Jihua Ding. Age-dependent seasonal growth cessation in Populus. PNAS (2023). https://doi.org/10.1073/pnas.2311226120
MicroRNAs play a role in regulating a broad range of biological processes, including development, cell proliferation and responses to environmental stress, among others. They are present in nearly all eukaryotic organisms, including mammals and plants, and are highly conserved throughout evolution.
For questions, please contact:
Professor Ove Nilsson
Umeå Plant Science Centre
Department of Forest Genetics and Plant Physiology
Swedish University of Agricultural Sciences
Phone: +46 702 869 082
Email:
https://www.upsc.se/ove_nilsson
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María Rosario García-Gil (left) and Totte Niittylä (right) will use the funding from the Swedish Research Council to study stress resilience and carbon sequestration in trees. Photos: Luna Niemi García (left), Fredrik Larsson (right) María Rosario García-Gil and Totte Niittylä receive funding from the Swedish Research Council to study stress resilience and carbon sequestration in trees. Both researchers are group leaders at UPSC and SLU. Within the last five years, researchers at UPSC have secured a total of seventeen grants from the Swedish Research Council including these two new grants.
The focus of María Rosario García-Gil’s research group is on forest tree genetics and breeding. She and her group are working mainly with the economically important tree species Norway spruce and Scots pine. They are investigating ways to improve traditional tree breeding practices using contemporary gene sequencing techniques and remote sensing tools, but they are also investigating physiological responses associated with tree adaptation to light and shade. In the approved project, she plans to investigate if an enhanced lignin synthesis can confer a better disease resilience in conifers under shade.
“In a previous study, my co-worker Sonali Ranade and I showed that Scots pine and Norway spruce populations from the North react differently to shade than those from the South,” says María Rosario García-Gil. “Usually, lignin synthesis is reduced under shade but in the Northern populations that we studied in comparison to Southern population it was enhanced. In parallel, defence-related genes were activated and we think this is an evolutionary adaptation to the shadier northern conditions. The question is if this adaption also confers a higher resilience against diseases which is what we would like to investigate further in this project.”
To answer this question María Rosario García-Gil and her colleagues plan to exploit multiple technologies including visual techniques like microscopy but also gene and metabolite analyses. Their goal is to gain a comprehensive understanding on how lignin synthesis and tree disease resistance are connected. Climate change is already now affecting tree and forest health due to pest spreading and insect attacks and the researchers think that their results will be valuable for a sustainable management of Norway spruce and Scots pine forests in Scandinavia.
Totte Niittylä’s research project is also connected to climate change and its impacts on forest ecosystems, but he will focus on a different aspect. His group’s expertise is in carbon allocation in trees, especially on how sugars from photosynthesis are used for wood formation. Their favourite tree model organism is hybrid aspen because of its ease of genetic manipulation and excellent genomic resources. Also in the new project, the group will work with hybrid aspen and investigate how trees draw carbon dioxide from the atmosphere and how the assimilated carbon is used for wood formation.
“The wood of trees is the single most important terrestrial sink of carbon dioxide. This means that forests are critical in the mitigation of climate change”, says Totte Niittylä. “Despite its importance, the mechanisms controlling carbon sequestration into wood are not well understood. The purpose of our project is to describe the molecular controls of this process. Our vision is that filling this knowledge gap will improve our ability to predict the impact of climate change on forest ecosystems.”
Totte Niittylä and his group plan to investigate how sugars are transported within the tree, how leaves and developing wood communicate to coordinate this process and how sugar metabolism and wood formation are connected. They will use state-of-the-art molecular biology methods to identify proteins that regulate the key metabolic pathways during wood formation and combine these methods with metabolite studies and tools for studying wood and tree phenotypes. Their aim is to contribute parameters on carbon uptake capacity of trees that will help to improve global climate models.
The two projects approved by the Swedish Research Council within Natural and Engineering Sciences:
- Project: To grow or to defend? - Deciphering defense-growth strategies in Scots pine and Norway spruce under local light conditions in Sweden
María Rosario García-Gil
Umeå Plant Science Centre
Department of Forest Genetics and Plant Physiology
Swedish University of Agricultural Sciences
Email:
https://www.upsc.se/rosario_garcia
- Project: Molecular control of carbon sequestration into wood
Totte Niittylä
Umeå Plant Science Centre
Department of Forest Genetics and Plant Physiology
Swedish University of Agricultural Sciences
Email:
https://www.upsc.se/totte_niittyla
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Dhruv Agrawal, Excellence of Choice postdoctoral fellow at the Department of Plant Physiology, UPSC, Umeå University. Photo: Mattias Pettersson, Umeå UniversityDhruv Agrawal's passion for microbiology has led him from India to an 'EC' postdoctoral fellowship at Umeå Plant Science Centre at Umeå University. His research focuses on understanding the role of protein complexes that help in the regulation of growth and development in model plant Arabidopsis thaliana.
What is your academic background?
“My academic journey reflects a strong commitment to advancing my knowledge in the field of microbiology and life sciences. I have completed a bachelor’s degree in microbiology at the University of Delhi in India. Subsequently, I pursued my passion for microbiology by earning a master’s degree from Guru Nanak Dev University in Amritsar. Building upon this foundation, I attained a PhD degree in life sciences, specializing in microbiology, also from Guru Nanak Dev University.”
How did you end up in Northern Sweden and at Umeå University?
“I discovered the vacant job posted on the 'Nature Careers' website. Umeå University's exceptional infrastructure, particularly the Umeå Plant Science Centre (UPSC) and Umeå Centre for Microbial Research (UCMR), captured my attention. The prospect of working with plants, coupled with the opportunity to delve into multi-subunit proteins systems, was the primary motivation behind my decision to apply for a postdoc fellowship. This unique combination of resources and research focus at Umeå University aligns with my professional aspirations.”
What is your research focusing on?
“My research is focused on the exploration of the COP9 signalosome (CSN) complex, with a particular emphasis on its functional and structural aspects within the model plant thale cress, Arabidopsis thaliana. It is fascinating to note that this multi-subunit proteins system exhibits a distinctive form in this botanical model.”
“I am genuinely thrilled to be immersed in the study of plant systems, and I approach my work with great enthusiasm. The prospect of delving into the intricate realm of plant proteins is both exciting and promising. My research in biological processes and mechanisms that govern the growth and development of plants, can also give valuable insights into the broader field of biology and biotechnology.”
Dhruv Agrawal works with the model plant thale cress, Arabidopsis thaliana. Photo: Mattias Pettersson, Umeå UniversityWhat is challenging and rewarding respectively with being a researcher?
“The role of a researcher is not without its share of challenges, including the pressures of meeting deadlines and the inevitability of uncertainty and occasional setbacks, it offers a range of profound and fulfilling rewards. The foremost among these is the intellectual gratification derived from delving into the unknown, unravelling complexities, and making novel discoveries.”
“In addition to personal and professional growth, research paves the way for societal advancement. The knowledge, innovations, and solutions generated through research contribute to the betterment of society, addressing critical challenges and improving the quality of life.”
Where do you see yourself in five years?
“I see myself in five years as a seasoned professional, actively engaged in projects that contribute to the betterment of society, and I aspire to be recognized for my dedication and impact in my chosen field. I intend to take on more challenging and impactful roles, assuming positions of greater responsibility that allow me to not only excel in my professional domain but also mentor and inspire others. Furthermore, I plan to expand my network and collaborations, fostering connections with like-minded individuals and organizations who share a passion for effecting positive change.”
What are your first impressions of Umeå and the Umeå University?
“My initial impressions of Umeå and Umeå University have been exceptionally favourable. Umeå's fusion of urban living and the surrounding natural beauty is not only inviting but also harmonious. The university's unwavering dedication to excellence, its celebration of diversity, and its culture of innovation are inspiring. I look forward to an intellectually enriching and personally fulfilling experience here.”
“The climatic contrast between Umeå and my previous residence in India is notable. The cooler weather here presents a new and exciting experience for me, with my first encounter with snowfall being an awesome and memorable moment.”
What is your driving force to do research?
“My driving force for conducting research in life science is a profound fascination with the intricate mechanisms of life, from molecular level to ecosystems. Life science research offers a unique opportunity to unravel the mysteries of biology, health, and the environment, and to contribute to advancements that can enhance human well-being and our understanding of the natural world.”
What drives Dhruv Agrawal in his research is a deep fascination with the intricate mechanisms of life, from the molecular level to ecosystems. Photo: Mattias Pettersson, Umeå UniversityMe in three words: Passionate, simple, organized
Interests: Music, sketching and movies
Favourite book: The perks of being a wallflower by Stephen Chbosky
Streaming: Biopics (biographical movies)
Listening to: Country music
Miss from home: Street food from the local vendors
The first Swedish word I learnt: Vatten
On my bucket list: Learn scuba diving
Favourite holiday spot: Summer evenings on the beach
Enjoy: Cooking, and it saddens me when I see the food go to waste
Text: Ingrid Söderbergh, UCMR & Umeå University
More information
Read more about the 'Excellence by Choice' Postdoctoral Programme
More information about Umeå Centre for Microbial Research (UCMR)
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Vladimír Skalický and Ioanna Antoniadi are working at the cell sorting instrument which allows separating differently labelled cell compartments (Photo: Asal Atakhani).
Research teams from Sweden and the Czech Republic have developed a novel method that allows to analyse low concentrated substances on the subcellular level. Using this method, the researchers demonstrated that plant growth substances are distributed unevenly in the different compartments of a plant cell. Although the method was initially established on plant cells, its potential extends to numerous research applications beyond plant science.
The study, published online in September in The Plant Journal Technical Advance, involved researchers from Umeå Plant Science Centre (UPSC), a collaboration between Swedish University of Agricultural Sciences (SLU) and Umeå University, from Palacký University and from the Czech Academy of Sciences.
Plant hormones, which are growth substances found in very low concentrations, regulate diverse developmental processes in plants. Karin Ljung’s and Ondřej Novák’s research groups had previously analysed plant hormones at the tissue and cellular levels, but the resolution of the analytical methods had not been sufficient to measure plant hormone concentrations inside a cell and in its compartments, the organelles.
Plant hormones are unevenly distributed within plant cells
“Based on the distribution of proteins responsible for transporting plant hormones within and between cells, we assumed that plant hormones themselves were also distributed unevenly within plant cells. However, this remained unproven until now”, says Karin Ljung who is professor at SLU and group leader at UPSC and has a longstanding collaboration with professor Ondřej Novák, who leads the Laboratory of Growth Regulators at Palacký University Olomouc and the Institute of Experimental Botany at the Czech Academy of Sciences.
The researchers named their new method “Fluorescence-Activated multi-Organelle Sorting” or FAmOS for short. They labelled four different organelles in the cell with distinct fluorophores - chemical compounds that emit specific colours of light when they are excited by light. Every of these organelles received a different label, and the researchers then sorted them according to the colour that the respective label emitted.
Simultaneous isolation of four different organelles
“We chose this approach because previous fractionation techniques were both too time-consuming and lacked common features. When using different methods to isolate, for example, the nucleus and the chloroplast, concentrations of plant hormones in the two separately isolated organelles were not comparable with each other”, says Ioanna Antoniadi who is working in Karin Ljung’s group. “It was very challenging to find the right conditions to keep the sorting time short while ensuring the stability of plant hormones, but finally, we managed to get it to work.”
The researchers labelled four different organelles (nucleus (Nu), Endoplasmic reticulum (ER), Chloroplast (Chl) and Mitochondrion (Mi); illustrated left) and separated them from the rest of the cell which consists mainly of the vacuole. Then, they measured the concentration of the plant hormones auxin (top right) and cytokinin (bottom right) in the different organelles. The colour range illustrates the amount of cytokinins in the different organelles: a dark colour corresponds to a high concentration, a light colour to a low concentration. Blue is used for Auxin concentration and red for Cytokinin concentrations. Illustration: Ondřej NovákExisting methods were optimised to measure minute plant hormone amounts
Another challenge the researchers encountered was the low concentration of the plant hormones in plant cells. After separating the organelles, the plant hormone concentration was measured within them using liquid chromatography coupled to tandem mass spectrometry. This technique is typically used to separate various compounds in a mixture based on their mass and then identify and quantify them based on their mass. While it had been previously used to measure different plant hormones in plant tissues, organs or cells, it had not been employed for minute amounts such as found in 200.000 organelles per sample.
“We were many times close to the detection limit of mass spectrometry. As comparison, one can imagine dissolving one teaspoon of the plant hormone cytokinin in an Olympic size swimming pool and then taking out only ten microlitres of this mixture for the analysis,” explained Vladimír Skalický who developed the method together with Ioanna Antoniadi as part of his PhD thesis in Ondřej Novák’s group at Palacký University, Olomouc.
“The amount of cytokinin in these ten microliters corresponds to the quantity of cytokinin in one ten-day old thale cress seedling, which is just about five centimetres long and served as the starting material for our experiments. We needed several attempts and comprehensive sets of control experiments until we ultimately succeeded.”
The new method has great potential for numerous future applications
The researchers believe that their new method has great potential for numerous future applications. It is not restricted to plant cells but can be applied to mammalian, algae or bacterial cells as well and allows to analyse other substances than plant hormones once the organelles are sorted and separated. This includes for example the measurement of other metabolites, proteins as well as gene activity at the subcellular level.
“It has been extremely important to develop this highly sensitive and robust method. It is efficient in terms of time and enables us monitor plant hormone concentrations and also other metabolites within the cell itself”, says Ondřej Novák. “Such high-resolution mapping of metabolites within isolated organelles will improve our understanding of metabolic and signalling processes within the cell.”
The article
Skalický, V., Antoniadi, I., Pěnčík, A., Chamrád, I., Lenobel, R., Kubeš, M.F., Zatloukal, M., Žukauskaitė, A., Strnad, M., Ljung, K. and Novák, O. (2023). Fluorescence-activated multi-organelle mapping of subcellular plant hormone distribution. Plant J. https://doi.org/10.1111/tpj.16456
For questions, please contact:
Karin Ljung
Umeå Plant Science Centre
Department of Forest Genetics and Plant Physiology
Swedish University of Agricultural Sciences
Email:
https://www.upsc.se/karin_ljung
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Nathaniel Street (left), Stephan Wenkel (middle) and Stefan Jansson (right) were highlighted during Umeå University's Annual Celebration Ceremony (photo: Samuel Pettersson).Last week, Umeå University held its Annual Celebration Ceremony. Three researchers from UPSC were highlighted during the ceremony. Nathaniel Street and Stephan Wenkel were installed as new professors and Stefan Janson officially received the 2023 Bo and Barbro Hammarström Award for his efforts to promote academic research and development.
During the Annual Ceremony, Umeå University honours its newly appointed honorary doctors, new professors, and award recipients. With two new professors and one award recipient, UPSC had a strong presence at this years’ ceremony. Both, Stefan Jansson and Nathaniel Street, have been working at UPSC and Umeå University for several years, while Stephan Wenkel was recruited as new professor earlier this year.
Umeå University’s Annual Celebration Ceremony spanned two days starting on Friday with the opening of an exhibition and a lecture by one of the new honorary doctors. On Saturday morning, all new honorary doctors, new professors and award recipients gave popular science lectures. The official ceremony, where honorary doctors were conferred, new professors were installed, and awards were presented, took place late in the afternoon on Saturday.
More information
More details about Umeå University’s Annual Celebration Ceremony
News about the 2023 Bo and Barbro Hammarström Award
More information about the research of the three UPSC researchers:
Stefan Jansson
Nathaniel Street
Stephan Wenkel
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The sight of trees swaying in the wind has captivated the imagination of artists and nature enthusiasts. However, for the trees themselves, this continuous mechanical stimulation can be a source of stress. A research team led by Ewa Mellerowicz from UPSC and SLU set out to study the effect of such repetitive flexing on aspen trees and found that the trees grew faster.
The study was published yesterday in the journal New Phytologist. Researchers from Umeå Plant Science Centre, a collaboration between Swedish University of Agricultural Sciences and Umeå University, were leading the study and were supported by researchers from RISE (Research Institutes of Sweden), Umeå University and from the Laboratory of Growth Regulators, a joint facility between the Faculty of Science, Palacký University, and the Institute of Experimental Botany, Czech Academy of Sciences.
It is long known that plants exposed to continuous mechanical stimulation, such as wind, adjust their growth and development. Trees that are repeatedly bent by the wind tend to grow shorter and sturdier as a defense against mechanical stress. However, the research team around Ewa Mellerowicz, group leader at UPSC and professor at the Swedish University of Agricultural Sciences, observed somewhat different results when they exposed aspen trees to recurrent flexing.
“We used an automated conveyor belt system carrying young aspen trees and applied flexing stress by moving the belt. Especially when the belt started to accelerate and when it stopped, the trees experienced low-intensity multidirectional stem flexures”, explains János Urbancsok, first author of the paper and former postdoc in Ewa Mellerowicz’s group. His colleague Evgeniy Donev, postdoc in the same group and shared first author of the paper, adds:
“Compared to control trees that were growing on a non-moving belt besides them, the flexed trees grew faster with increased stem diameter and root growth. Similar effects have been observed before in bent or touched plants, but we were astonished to also see an increased shoot elongation and leaf size. This was not reported previously.”
The researchers speculated that stem elongation and leaf expansion might have been stimulated by vibrations associated with the shaking which was applied to the plants when the conveyor belt was abruptly accelerated or brought to a halt. They knew from other studies that vibrations coming for example from sound can stimulate growth in general. This led them to delve deeper and investigate if they could find more parallels or differences in response to vibration or other mechanical stimulation such as bending or touching.
To start, they analysed the properties of the “flexure wood” - the wood that is formed under mechanical stress such as stem flexing. They discovered that this wood contained more cellulose and formed gelatinous fibres, similar to the wood fibres formed on the upper side of a bent tree. These fibres were much easier to convert into sugars which makes “flexure wood” interesting for biofuel production.
In a next step, the researchers examined differences in gene activities and concentrations of plant hormones. Plant hormones are low-concentrated growth-regulating compounds known to be involved in stress responses, especially regulating gravity-induced changes that occur for example under bending. Most of the changes in gene activity and plant hormone concentrations were in line with prior findings but the researchers also discovered something new: changes in the metabolism of polyamines.
“We are not sure yet how to interpret these results”, says Ewa Mellerowicz. “Polyamines play important roles in regulating plant growth and development but also in stress responses. It might be that polyamines were just not analysed in previous studies, or they are only induced by vibration and not by bending or other forms of gravistimulation. These questions need to be addressed in future studies, but we believe that our study gives novel and important insights into the mechanobiology of higher plants which could result in practical application like for example for plant cultivation practices.”
The article
Urbancsok, J., Donev, E.N., Sivan, P., van Zalen, E., Barbut, F.R., Derba-Maceluch, M., Šimura, J., Yassin, Z., Gandla, M.L., Karady, M., Ljung, K., Winestrand, S., Jönsson, L.J., Scheepers, G., Delhomme, N., Street, N.R. and Mellerowicz, E.J. (2023), Flexure wood formation via growth reprogramming in hybrid aspen involves jasmonates and polyamines and transcriptional changes resembling tension wood development. New Phytol. https://doi.org/10.1111/nph.19307
For questions, please contact:
Professor Ewa Mellerowicz
Umeå Plant Science Centre
Department of Forest Genetics and Plant Physiology
Swedish University of Agricultural Sciences
Phone +46 (0)90 786 8367
Email:
https://www.upsc.se/ewa_mellerowicz
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Karin Ljung receives the Arvid Lindman medal from SLU (Photo: Elisabeth Ohlson Wallin)
Karin Ljung, group leader at UPSC and professor at SLU, has been awarded the Arvid Lindman medal for her “outstanding contribution to research, teaching and supervision in the fields of forest biotechnology and experimental plant biology”. The Arvid Lindman medal is an award that SLU has dedicated to excellence within forest research. It was officially awarded to Karin Ljung at SLU’s doctoral award ceremony last Saturday.
Karin Ljung has been a research group leader at UPSC since 2005 and was promoted to professor at SLU in 2015. Her research at UPSC has mainly revolved around investigating the roles of plant growth regulators or hormones in root development and the integrative coordination of above and below ground growth. Apart from her “outstanding contribution to research, teaching and supervision”, her “exceptional contribution to the high international ranking of both UPSC and SLU within plant science research” was also highlighted in the motivation for the award.
Karin Ljung has also developed advanced methods both for hormone profiling in plant tissues and the analysis of hormone distribution and metabolism at cellular and sub-cellular resolution. Her successful research has resulted in multiple publications in high-ranking journals and she has been included since 2014 on the Clarivate Analytics list of the world’s highest-cited researchers. Besides her significant scientific contributions, Karin Ljung has taken over several commitment of trusts within UPSC, at SLU’s Faculty of Forest Science and on national and international levels, for example as a member of the Scientific Advisory Board for the European Forest Institute.
Karin Ljung could not join the doctoral award ceremony last Saturday in Uppsala and was presented the Arvid Lindman medal in absentia. At this ceremony, new doctors who have defended their theses since the last ceremony as well as honorary and jubilee doctors are officially conferred and medals and awards given by SLU are presented. Even though Karin Ljung could not be present at SLU’s doctoral award ceremony in Uppsala last Saturday, UPSC was well-represented.
Two new doctors from the Department of Forest Genetics and Plant Physiology who defended their PhD thesis before August 31st 2023 received their insignia, as well as honorary doctor Malcolm Bennett, professor at the University of Nottingham. He was nominated by the Faculty of Forest Science due to his important long-standing collaborations with researchers at UPSC. Furthermore, Stéphanie Robert, also group leader at UPSC and professor at SLU, was given the honour of holding the inspirational lecture to the new doctors at the ceremony and she presented her research on the regulation of plant cell shape.
New Honorary doctor Malcolm Bennett and Stéphanie Robert, invited honorary lecturer, after SLU's Doctoral Award Ceremony (photo: Rishikesh Bhalerao)
Stéphanie Robert was given the honour of holding the inspirational lecture at the beginning of SLU's Doctoral Award Ceremony (photo: Simon Andersson)
More information about the Arvid Lindman medal
Arvid Lindman was a former Swedish prime minister who in 1915 was the first chairman of the board of the Forestry College, which is now SLU’s Faculty of Forest Science. The SLU Board chooses the medal awardee based on the suggestion of the Faculty of Forest Sciences. The medal will be awarded whenever the Faculty Board thinks it is appropriate. It is a reward for particularly meritorious scientific achievements and is awarded in connection with the annual doctoral award ceremony in October.
More information about SLU’s Doctoral Award Ceremony:
https://www.slu.se/en/about-slu/academic-ceremonies/doctoral-award-ceremony-2023/
You can also find the live broadcast of the doctoral award ceremony 2023 and of the honorary doctor’s lectures there.
Additional information
An interview with Karin Ljung for the International Day for Women and Girls in Science
More information about Malcolm Bennett’s appointment as honorary doctor
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Text: Siamsa Doyle & Anne Honsel
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The PhD students Laura Tünnermann and Tinkara Bizjak are organising the seminar series "Outside of Academia" at UPSC (photo: Varvara Dikaya).
Which career possibilities exist for (plant) scientists outside of academia? Laura Tünnermann and Tinkara Bizjak, both PhD students at Umeå Plant Science Centre, thought that it is not talked enough about this at the university and started to organise the seminar series “Outside of Academia”. Read more about their motivation and how they choose topics and speakers in this interview with them.
You started beginning of this year to organise the seminar series “Outside of Academia”. What motivated you to start this seminar series up at UPSC?
Laura Tünnermann: At the UPSC PhD and Postdoc retreat 2022, it was mentioned that a similar seminar called “Careers outside academia” was organized by former UPSC scientists. We thought that this was a great way to show different career options.
Tinkara Bizjak: Exactly, when you start a PhD it is assumed that you stay in academia, so you are not presented with other career options. That is why we wanted to revive this seminar series.
What is the purpose of this seminar series and how does the format look like?
Tinkara Bizjak: The purpose of this seminar is very simple - we want to show different career options that are waiting for scientists outside of academia.
Laura Tünnermann: About the format, we are trying to organize a seminar once a month. The speakers have about 30 – 40 min to introduce themselves, their background, and their current position. It is very important for us that the speakers explain why and how they left academia. After the presentation, we plan time for a question-and-answer session.
Tinkara Bizjak: The seminar is also always followed by a lunch with the speaker to enable further networking. And we can only encourage everybody to sign up and join the lunch!
How do you choose topics and search and engage speakers?
Laura Tünnermann: We try to find career options that people might not be aware of but are relevant to our participants, for instance, a patent attorney. When we select our speakers, we are looking for someone with a plant science background who did a PhD or even a postdoc.
Tinkara Bizjak: We try to focus some of the seminars on the industry in and around Umeå. We noticed a great interest of our participants in job opportunities in Umeå. Also, anyone who has an idea or a wish can contact us and we try to address it with a seminar.
Laura Tünnermann: After we decide on a topic, we try to find suitable speakers and companies and contact them by email.
What was most challenging and what most inspiring for you so far?
Tinkara Bizjak: The most challenging is to get the contacts. Sometimes it is hard to find their email or get an answer.
Laura Tünnermann: I agree, that is very frustrating, but I think the good feedback from our participants is worth it.
You have so far organised 3 different seminars inviting former researchers that are now working with patents, or in different local companies. Which topics are you planning to cover next?
Tinkara Bizjak: In October we are inviting two speakers who have spent 20 years in academia before switching to the industry. This will be followed by a seminar in November about being a scientific illustrator.
Laura Tünnermann: For next year, we are planning seminars about how to start your own company with the help of the Umeå Biotech Incubator. We are also trying to contact potential speakers from bigger companies like Eurofins or Qiagen.
Did you decide already which direction you would like to go after your PhD – inside or outside of academia?
Tinkara Bizjak: I am not sure yet, but I am leaning towards leaving academia at some point.
Laura Tünnermann: I have not decided yet either, but I hope organizing these seminars will help me with the decision.
More about the "Outside of Academia" Seminar series
Laura Tünnermann and Tinkara Bizjak plan to organise about five to six seminars per year in the frame of the "Outside of Academia" seminar series. The topics they covered so far were "Science & Law" and "Industry in Umeå" with contributions from Nordic Biomarker and Arevo. The next and fourth seminar with the topic "Postdoc in plant science – and then? Two career options" will take place on Friday next week, 13th of October. The speakers will be Rumen Ivanov, regulatory affairs manager at KWS in Germany, and Tzvetina Brumbarova, project manager at the Clinical Trials Centre Cologne, Germany. Both worked first as postdoc and senior researcher in academia before switching profession.
More information about the upcoming seminar on October 13 and the link to the registration form here
Contact:
For questions or suggestions please contact Laura Tünnermann (