J4A1095 1920x1080 TNasholm photoJohan MarklundTorgny Näsholm is awarded the 2018 Marcus Wallenberg Prize. Photo: Johan Marklund

Torgny Näsholm discovered that amino acids play an important role as nitrogen source for plants. He receives now the Marcus Wallenberg Prize 2018 for his ground-breaking research. 

Please have a look on the Marcus Wallenberg Foundation homepage for more information:

NatStreet teaching 1920x1080Photo: Kathryn Robinson

The plant geneticist and lecturer at the Department of Plant Physiology, Nathaniel Street, is awarded the pedagogical prize from the Faculty of Science and Technology. The prize jury motivated its decision due to his outstanding ambition, good organization and strong interest in developing new ways of teaching. Nathaniel Street will receive the prize during the Spring graduation ceremony of Umeå University on the 19th of May.

“I was on the Ski lift and checked my emails when I found out that I was awarded for the prize”, tells Nathaniel Street. “I was so surprised that I had to read the message twice to be sure that it was true. It is fantastic to know that the efforts made for teaching are acknowledged and appreciated. I really did not expect this, especially because there are so many other excellent teachers in our institute.”

Nathaniel Street came as a postdoc to Umeå University in 2007. In 2011, he became Assistant Professor and is since January 2016 Associate Professor at the Department of Plant Physiology.

During his time at Umeå University, he has fast developed his teaching skills further. He became the course leader of the department’s genomics courses in 2011 and has refined the course since then. Nathaniel Street is also teaching on the courses Bioinformatics and Genome Analysis and Microbiology and Basic Molecular Biology at Umeå University as well as the course Plant Biology for Future Forestry at the Swedish University of Agricultural Sciences (SLU).

The prize motivation emphasizes Nathaniel Street’s extremely careful preparation of his teaching. He gives well prepared and clear lectures that are greatly appreciated by the students and he is continuously improving his teaching methods. Among others, he has introduced interactive and student-led discussions, new practical classes in the lab and discussions on ethics. Several of these initiatives have subsequently been taken over by other teachers at the institution.

“He involves both his own research group and the bioinformatics platform at the Umeå Plant Science Centre in his work and successfully creates extremely smooth ways of teaching, that not only allow the students to get in contact with actual research, but are also very interesting for the research itself”, is stated in the prize motivation. “His high competence in both plant biology and genetics as well as in advanced computing has made this possible.”

Nathanial Street focuses his research on finding the genes that control natural variation and he is analysing microbial communities that are living close together with forest trees. His ambition is to combine his research interest with his educational ambition and strong willingness to develop his teaching methods further.

“My hope is to convey my own fascination and interest in my research area. It can be a challenging area to teach because it is changing very fast, but I try to keep the courses up to date. I do not want the students to just sit and listen to me. It is fun to think of new ways to motivate the students to learn together and from each other and to help them develop skills to learn independently in the future. The courses I have attended at the University Education and Teacher Support (UPL) have been a great inspiration for this.”

Link to the Swedish press release

For more information, please contact:

Nathaniel Street
Associate Professor
Umeå Plant Science Centre
Department of Plant Physiology
Umeå University
Phone: 090-786 54 73
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Bud from the model organism hybrid aspen (Populus tremula x Populus tremuloides); Photo taken by Pal MiskolcziBud from the model organism hybrid aspen (Populus tremula x Populus tremuloides); Photo: Pal Miskolczi

For trees in boreal and temperate climates, it is important that buds do not burst precociously, but only when it's spring for real. Therefore, the buds are put in dormancy in the autumn, which means they have to go through a long cold period before they slowly become susceptible to the signals of spring. The mechanism behind this is revealed in a new study led by Rishi Bhalerao from UPSC, recently published in the journal Science.

Trees are amongst the longest-living organisms on Earth, and some species can live for thousands of years. One of the key mechanisms that enable such a long life is their synchronization of growth with change in seasons. For example, in temperate and boreal ecosystems, trees stop their growth and establish dormancy prior to the advent of winter. Growth cessation and dormancy establishment is a key adaptive mechanism for winter survival, since failure to cease growth and establish dormancy can result in fatality from extreme low temperatures in the winter.

How trees know when to stop their growth and establish dormancy is a question that has been of interest to researchers since a long time. That growth stops in response to the decrease in daylight during autumn has been well understood. The establishment of dormancy, which means that buds cannot burst before they have experienced a long cold period, and are not awakened by short warm periods during winter, has been more of a mystery. The recent article in Science, however, provides an important insight into how winter dormancy is regulated in perennial trees.

What the researchers could show is that the so-called plasmodesmata, channels that connect different cells with each other, are closed by the deposition of callose, a polysaccharide, in response to the shortening of day length in the autumn. The blockage of the plasmodesmata prevents cells from receiving growth promotive signals, thereby maintaining growth arrest and establishing dormancy in the buds.

The researchers also show that short-day induced dormancy is regulated by the plant hormone abscisic acid which activates (among others) the production of the callose that is used to block the plasmodesmata. Once blocked, a long exposure to low temperatures is needed to slowly re-open the plasmodesmata again, so that the growth-inducing signals can reach the buds and stimulate the growth in the buds in the spring.

"Interestingly, some of the facets of the dormancy regulation mechanism described in our paper have been observed in winter wheat as well as characean algae, suggesting that this mechanism is probably ancient and evolutionarily conserved", says Rishikesh Bhalerao.

The study was conducted using hybrid aspen, which is a model plant in tree research.

The study has been conducted by a research team led by Rishi Bhalerao from SLU's Department of Forest Genetics and Plant Physiology and the Umeå Plant Science Center. The colleagues come from SLU in Alnarp, Uppsala University, University of Helsinki, Cambridge University, Monash University and the University of Environmental and Life Sciences in Norway.

Link to the Swedish press release on the SLU homepage

More information

Contact person
Rishikesh P. Bhalerao, Professor
Umeå Plant Science Centre
Department of Forest Genetics and Plant Physiology
Swedish University of Agricultural Sciences, Umeå
+46 (0)90-786 84 88, +46 (0)70-678 37 32, This email address is being protected from spambots. You need JavaScript enabled to view it.


The article
S. Tylewicz, A. Petterle, S. Marttila, P. Miskolczi, A. Azeez, R. K. Singh, J. Immanen, N. Mähler, T. R. Hvidsten, D. M. Eklund, J. L. Bowman, Y. Helariutta, R. P. Bhalerao. 2018. Photoperiodic control of seasonal growth is mediated by ABA acting on cell-cell communication. Science 10.1126/science.aan8576 (2018). 
DOI: 10.1126/science.aan8576

Direct link to the article in Science

Text: David Stephansson (SLU)

Mateusz IMG 7837 Edited 1920x1080Mateusz Majda and his opponent Malcolm Bennett from the University of Nottingham. Photo: Stéphanie Robert
On Monday, 12th of February, Mateusz Majda has defended his PhD thesis with the title "Role of the cell wall in cell shape acquisition". In his thesis, he has analysed how the cell wall influences the shape of a cell. He focused on so called pavement cells that are forming the outmost cell layer of leaves and have a very specific jigsaw puzzle-shape. The public defence took place at 9:30h in Björken at SLU Umeå. Faculty opponent was Malcolm Bennett from the University of Nottingham, UK, supervisor Stéphanie Robert.

If you are interested in reading more about Mateusz Majda's findings, have a look here: https://www.upsc.se/about-upsc/news/5235-the-growth-of-puzzle-piece-shaped-leaf-cells-gets-an-explanation.html

Link to the doctoral thesis: https://pub.epsilon.slu.se/15263/

IMG 4096 1920x1080Three of the scientists (from left to right): Åsa Strand, Tamara Hernández-Verdeja, Tim Crawford (photo: Anne Honsel)
[2018-01-03] It has long been assumed that light activates chloroplastic gene expression via so-called thiol-mediated redox regulation. However, the mechanism giving rise to this regulation has remained elusive until now. Åsa Strand and her group at the Umeå Plant Science Centre have now identified the components involved in this redox regulatory mechanism. Their results are published in the journal Nature Communications.

The chloroplast is the place in the cell where photosynthesis occurs. When a seedling comes out of the soil, it gradually turns green, and during this greening process the photosynthetic machinery in the chloroplasts develops and becomes fully functional. The establishment of photosynthesis is a complicated process that involves the activation of gene expression in the chloroplast in response to light. Åsa Strand and her group identified a component that connects the light signal to the activation of gene expression in the chloroplast.

It was demonstrated that certain proteins, called thioredoxins, transfer electrons, primarily derived from light, to the protein PRIN2 (PLASTID REDOX INSENSITIVE2). PRIN2 becomes reduced and changes its structure from a dimer (i.e. two PRIN2 proteins are bound together) to a monomer (single proteins). The PRIN2 monomers then activate photosynthetic gene expression in the chloroplast. This type of regulation is called thiol-mediated redox-regulation because the functional chemical group mediating the transfer of electrons is the sulphur containing thiol group.

“We identified PRIN2 several years ago. We knew that it was sensitive to redox changes and that it was required for normal gene expression in the chloroplast”, explains Åsa Strand. “We have now shown that PRIN2 is regulated by light via thioredoxins and that it then activates a protein complex called PEP. This protein complex is responsible for expression of the photosynthesis related genes in the chloroplast.”

The protein complex PEP (plastid-encoded RNA polymerase) reads the information stored in the DNA of the chloroplast genome and copies it into RNA (ribonucleic acid). RNA serves then as template to translate the information stored in the DNA into proteins. PEP is a large protein complex that needs several associated proteins to gain its full function. One of these associated proteins is PRIN2.

The proteins required for a fully functional photosynthetic machinery are partly encoded in the nucleus and partly in the chloroplast genome of a cell. Thus, some form of communication between the two cellular compartments is required to ensure that all components are available at the right time during seedling development. PRIN2 plays an essential role in the communication between the two compartments because the status of the PEP complex links the functional state of the chloroplast to the nucleus, enabling the plant to synchronize expression of photosynthetic genes from the nuclear and chloroplast genomes during seedling development.

FinalVersion 1920x1020
Schematic overview about the molecular mechanism linking light and chloroplast development
(created by Daria Chrobok): When light is received for the first time by the cell, etioplasts (top left side) develop into chloroplasts (top right side). The photosystem II (PSII) starts to use the light energy to split water. The released electrons are transferred over the electron transport chain consisting of plastoquinone (PG), cytochrome b (Cyt b6f) and plastocyanine (PC) to the photosystem I (PSI). From PSI the electrons are transferred over several steps to thioredoxin which becomes reduced and then transfers the electrons further to PRIN2. PRIN2 can now activate PEP and PEP activates the expression of the photosynthesis related genes.

The article
Manuel Guinea Díaz, Tamara Hernández-Verdeja, Dmitry Kremnev, Tim Crawford, Carole Dubreuil & Åsa Strand. Redox regulation of PEP activity during seedling establishment in Arabidopsis thaliana. Nature Communications, (2018) 9:50, DOI:10.1038/s41467-017-02468-2

For more information please contact:
Åsa Strand
Umeå Plant Science Centre
Department of Plant Physiology
Umeå University
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
Phone: +46907869314
IMG 4122 1920x1080From left to right: Linn Fransson (Agrisera), Anna Gustavsson, Joanna Porankiewicz-Asplund (Agrisera), Catherine Bellini (Chair of the UPSC board); photo: Anne Honsel
[2017-12-12] The winner of the UPSC Agrisera Prize 2017 was announced today during the UPSC Christmas lunch. The prize is awarded to Anna Gustavsson for her contribution to promote cell biology research at UPSC.

Anna Gustavsson is honoured for her effort in developing and improving the UPSC confocal laser scanning microscopy/macroscopy platform and the platform services. Her useful advices helped to improve the work environment at UPSC and she contributed significantly to several cutting-edge research publications. Anna Gustavsson’s achievement benefitted a lot from Agrisera products emphasizing that she is a very good candidate for the prize even though this was no required criteria this year.

The UPSC Agrisera Prize was presented by Linn Fransson and Joanna Porankiewicz-Asplund from Agrisera and by the chair of the UPSC board, Catherine Bellini. The prize is awarded every year to a PhD student, Postdoc or technician at UPSC for excellent scientific achievement and positive contributions to improve the UPSC working environment. It is a personal cash prize in form of a check and can be used for travel costs.

20170808 155930 ASchneider 1920x1080Unfertilized control plot of Scots pine at the field site "Rosinedal", Sweden; photo: Andreas Schneider
Last week, SciLifeLab announced that they will support 14 sequencing projects with 33 million SEK. The project from Nathanial Street and his co-applicants Vaughan Hurry, Torgny Näsholm and Sandra Jämtgård is one of them. They will use metagenomics and metatranscriptomics to analyse the effect of various types of nitrogen fertilisation on the diversity of the belowground metacommunity.

The belowground metacommunity describes the community of all microbes, e.g. fungi and bacteria, that are living in the soil and possibly interact with each other and with plant roots. Metagenomics studies help to resolve the composition of a metacommunity while metatranscriptomics gives insight in the activity and function of the microbes in a metacommunity. Nathanial Street and his co-applicants will use these tools to understand how nitrogen fertilisation influences the diversity of the metacommunity and the processes within the community.

The researchers will compare the metacommunity diversity in Scots pine forest stands that have been fertilised for a short period with inorganic or organic nitrogen. They will also analyse the effect of a long-term fertilisation with inorganic nitrogen as well as the development of the metacommunity many decades after the last nitrogen fertilisation was applied.

SciLifeLab, the Swedish national centre for molecular biosciences, has started the national sequencing project initiative to provide sequencing support for large-scale genomic research in Sweden. This initiative comprises two programs: the Swedish Genomes Program and the Swedish Biodiversity Program. The project from Nathanial Street and his colleagues is part of the Swedish Biodiversity Program that is directed to projects studying genomic variability in nature. The awarded funding is assigned to subsidize sequencing costs.

Link to the press release from SciLifeLab:

Title of the project:
Diversity impacts on the belowground metacommunity associated with contrasting nitrogen fertilization sources

For more information, please contact:
Nathanial Street
Department of Plant Physiology
Umeå University
Phone: +46 (0)90 786 5473
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
Press release CC1 mod 1920x1080Claudia Colesie working in the Antarctica. Photo: Nadine Borchhardt
Short periods of increased temperature can push Antarctic lichens to their physiological limits and therefore cause a sever survival threat. This is the result of a study from an international research team that analysed the acclimation potential of several Antarctic lichen species. Claudia Colesie, lead author of the publication and postdoctoral researcher at UPSC, and her colleagues concluded that increased temperatures will influence future species composition in the Antarctic vegetation and lead to a species loss. Their study is published in the journal Global Change Biology.

In recent years, the Antarctic Peninsula has experienced fast regional climate change. The vegetation in this extreme environment is dominated by lichens and non-vascular plants, such as mosses. The team, comprising of researchers from Sweden, Germany and New Zealand/Spain, wanted to understand how lichens respond to increasing temperatures in order to assess the risk of global warming for the vegetation on the Antarctic Peninsula.

“The Antarctic Peninsula serves as an early warning system for the effects of climate change on species and ecosystems,” explains Claudia Colesie who works at the Swedish University of Agricultural Sciences. “A lichen is a composite organism that is formed by a symbiosis between algae or cyanobacteria and a fungal partner. The algae or cyanobacteria are the energy producing partners in this symbiotic relationship and also called photobionts. In our study we show that 15°C mark the upper limit for Antarctic photobionts to survive in the lichen symbiosis.”

The temperature-driven effects on the lichens energy balance varied between different species. For example, one species endemic to the Antarctic and the southernmost parts of South America could not acclimatise to increased temperatures and the photobiont died. On the other hand, a wide spread lichen species, which does not only occur in the Antarctic but also in alpine and arctic environments, could recover its energy balance when exposed to higher temperatures.

“This lichen species was considered to have a broader ecological amplitude, i.e. the limits of environmental conditions within which the organism can live are wider. We did not at all expect to see this fast rate of acclimation to higher temperatures”, says Claudia Colesie. “Based on these results, we suggest that species with a higher physiological plasticity will be favoured with ongoing temperature shifts in the Antarctic. The consequential homogenisation of the local vegetation becomes an additional threat for this pristine environment, with severe influences on the function and productivity of the ecosystem.” 

Studies on acclimation processes in Antarctic organisms and the corresponding risk assessments are particularly useful to predict the effects of global warming because colder climates are more responsive to increased temperatures than warmer regions. However, the different sensitivity of lichen species that co-occur spatially close, makes it very difficult to predict how the future community composition may look like in the Antarctic.

Lichens occur worldwide under different environmental conditions. Several species are adapted to survive in some of the most extreme environments on Earth like the Antarctic. The lichen fungus (mycobiont) hosts the algae or cyanobacteria and forms the lichen thallus that provides shelter from the environment and may attach the lichen to the ground. In return, the fungus receives carbohydrates from the photosynthesising photobionts (algae or cyanobacteria). The symbiosis allows both partners to extend their ecological amplitude and expand their distribution.

Press release CC2 mod 1920x1080Overview of Livingston Island with the Spanish research station Juan Carlos I in the back. The samples for this studywere collected here. Photo: Claudia Colesie
The article
Claudia Colesie, Burkhard Büdel, Vaughan Hurry & Thomas Green. Can Antarctic lichens acclimatise to changes in temperature? Global Change Biology. Accepted Author Manuscript. doi:10.1111/gcb.13984


For more information please contact:

Claudia Colesie
Umeå Plant Science Centre
Department of Forest Genetics and Plant Physiology
Swedish University of Agricultural Sciences
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
Phone: +46(0)70-7660481

Rosario Garcia5060 042409 MPN 1150x766

Last Thursday, Formas officially approved a new project led by Rosario García Gil, group leader at UPSC. The project aims to compare different wood structures that have developed during evolution. The researchers want to identify key regulators of wood formation that might be useful for optimising modern tree breeding.

Using genetics and genomics tools, Rosario García Gil and her group will analyse which factors are involved in regulating wood formation in different woody plant species. They will compare two angiosperm and two gymnosperm tree species that have developed different wood architectures during evolution.

In angiosperms (or flowering plants), wood vessels and fibres, which are certain specialised cell types, conduct water along the stem. Gymnosperms (vascular plants with seeds but without flowers or fruit) have not evolved water conducting vessels. Solely wood fibers perform the water transport. These fibers are often longer and have a different lignin composition than in angiosperm trees.

“Regarding wood architecture, aspen and spruce are typical representatives of angiosperm respective gymnosperm trees”, says Rosario García Gil. “We want to compare wood formation in both tree species with each other but also include two exotic tree species that have evolved an intermediate wood architecture.”

These two species are Gnetum gnemon, a gymnosperm tree that has evolved vessels, and Drimys winteri (Winteracea), an angiosperm tree that has lost vessels during evolution.

“By comparing the genetic architecture of these different woody species, we hope to identify key factors involved in wood formation and provide a novel molecular tool box for trans-species breeding of wood properties”, explains Rosario García Gil. “This information will contribute to the shift towards a bio-based economy”.

Rosario García Gil, Associate Professor at the Swedish University of Agricultural Sciences, started her research group at the Umeå Plant Science Centre in 2005. She focusses in her research on forest tree genetics and breeding with emphasis on traits like wood formation that have an economic value.

Title of the granted project:
Inter-species comparative Evo-Devo study for the dissection of the genetic architecture of wood properties: Towards a forest bio-based economy

For more information please contact:
Rosario García Gil
Umeå Plant Science Centre
Department of Forest Genetics and Plant Physiology
Phone: +46 (0)90 786 8413
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
1U5A0746 2 1920x1080Mateusz Majda. Photo: Stéphanie Robert

The cells in the outmost layer of leaves have irregular shapes, which help them to interlock with each other like jigsaw puzzle-pieces to form a sturdy layer. How this growth pattern is achieved has been debated, but now a team led by SLU researchers has proposed a possible mechanism.

The study aims to understand how plant cells get shaped. The form of the plant cell can be very specific, like the jigsaw puzzle-shaped pavement cells in the outer epidermal layer of plants. It was previously thought that these cell types are formed by locally different expansion rates, i.e. that the cell wall around the cell grows differently fast and that this causes the local bending of the cell wall inwards or outwards.

In this study, Mateusz Majda together with colleagues from SLU and seven other universities have used a computational modelling approach that shows that a differently growing cell wall cannot alone explain the specific form of the jigsaw puzzle-shaped cells. The cell wall surrounding the cell also needs to have varying mechano-chemical properties – a cell wall is easier to bend where it is "softer" than where it is more rigid. The researchers could prove this by using advanced microscopy techniques in combination with genetic studies with different cell wall mutants.

"The cell wall is composed of different sugars and some proteins. We have shown that cell growth and shape acquisition is controlled by very local changes in the distribution of sugars", says Mateusz Majda at Umeå Plant Science Centre. He is a doctoral student at SLU and first author of the article.

By analyzing mutants with a wide range of defects related to major cell wall components, the team first showed that even minor alterations in the cell wall composition lead to severe defects in the geometry of the leaf pavement cells. A computational modeling approach then suggested that mechanical heterogeneity in the cell wall is needed to initiate the interdigitated shape of pavement cells in an epidermis that is under tension. Such heterogeneities were detected by atomic force microscopy (AFM) in straight cell walls prior to and at a very early stage of lobe formation. In addition, the direction of bending from the mechanically stronger toward the mechanically weaker cell wall domain, as predicted by the model, was confirmed by AFM in cell walls at the very early stage of wall lobing.

"Cell walls are the main component of wood and represent the majority of the industrial terrestrial biomass. In the long-term perspective, this research in understanding cell wall biosynthesis in unprecedented detail will permit us to engineer or develop new approaches to modulate the biomass", says Stéphanie Robert, senior lecturer at SLU's Department of forest genetics and plant physiology in Umeå, and lead author of the article.

The article was published on November 6th in Developmental Cell by researchers from the Swedish University of Agricultural Sciences and colleagues from Uppsala University, Université de Lyon, Lund University, University of Wroclaw, Umeå University, University of Potsdam and University of Cambridge.

Fig Majda 1920x1080llustration of jigsaw puzzle shaped epidermal cells of a leaf. The coffee bean shaped structures are the stomata. Illustration: Mateusz Majda

Link to the Swedish press release on the SLU homepage

The article

Mateusz Majda, Peter Grones, Ida-Maria Sintorn, Thomas Vain, Pascale Milani, Pawel Krupinski, Beata Zagorska-Marek, Corrado Viotti, Henrik Jönsson, Ewa J. Mellerowicz, Olivier Hamant & Stéphanie Robert. Mechanochemical polarization of contiguous cell walls shapes plant pavement cells. Developmental Cell 43, 290–304, November 6, 2017.

More information

Contact persons
Mateusz Majda, PhD student
Umeå Plant Science Centre
Department of Forest Genetics and Plant Physiology
Swedish University of Agricultural Sciences
+46 (0)90-786 55 16, This email address is being protected from spambots. You need JavaScript enabled to view it.

Stéphanie Robert, Senior Lecturer
Umeå Plant Science Centre
Department of Forest Genetics and Plant Physiology
Swedish University of Agricultural Sciences
+46 (0)76-767 45 95, This email address is being protected from spambots. You need JavaScript enabled to view it.

Text: Mateusz Majda, Stéphanie Robert, David Stephansson