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:

Link to the doctoral thesis:

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.

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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
IMG 4001 1920x1080
Vetenskapsrådet granted three research projects associated with UPSC. The projects from Catherine Bellini, Ewa Mellerowicz and Xiao-Ru Wang will address adventitious root initiation, signalling from secondary cell walls and the processes of hybrid speciation and adaptation to extreme habitats.

Catherine Bellini, Professor at Umeå University and group leader at UPSC, works on adventitious root initiation. Adventitious roots play an important role for plant vegetative propagation. Many factors are involved in the initiation of adventitious roots and Catherine Bellini’s group has identified several of them. The aim of the approved project is to understand better how those different factors act together and cross-talk with each other.

Ewa Mellerowicz, Professor at the Swedish University of Agricultural Sciences and group leader at UPSC, focuses in her research on wood formation. Wood is produced by the activity of the vascular cambium, which consists of actively dividing cells. Ewa Mellerowicz's group and others have recently observed that certain modifications of the secondary cell wall composition of wood cells lead to increased cambial growth. With the new funding from VR, they want to identify the key players that are involved in this novel signalling pathway.

One research focus of Xiao-Ru Wang, Professor at Umeå University and associated group leader at UPSC, is to understand which role hybridization between species plays for the evolution of new species. Hybridization is a very dynamic process that can generate genetic diversity for novel adaptation. With the new project, Xiao-Ru Wang and her group want to understand the process how new hybrids develop, and how they evolve to colonize new ecological niches.

Titles of the approved projects:
Catherine Bellini: Control of adventitious root initiation in Arabidopsis thaliana: deciphering the increasing complexity of molecular cross-talks
Ewa Mellerowicz: Novel signalling pathways from secondary walls
Xiao-Ru Wang: Dynamics of hybrid speciation and adaptation to extreme habitats

More information:
Catherine Bellini
Umeå Plant Science Centre
Department of Plant Physiology
Umeå University
Phone: +46 (0)90 786 9624
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

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: This email address is being protected from spambots. You need JavaScript enabled to view it.

Xiao-Ru Wang
Department of Ecology and Environmental Sciences
Umeå University
Phone: +46 90 786 99 55
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

anatomy course 1 1920x1080
The one week lasting intensive PhD course provided a brief overview of wood organization, chemistry and structure in conifers and hardwoods, from the molecular level to the tissue organization level, followed by an update on molecular, genetic and physiological aspects of wood cell differentiation and cell wall formation. Current tools for studying wood structure and chemical composition, as well as the bioinformatics tools available for wood biology were introduced with practical demonstrations. Lectures and seminars were given by experts in the field.

Read more here
plant biology1 1920x1080
The new Master’s programme called “Plant Biology for Sustainable Production” is intended for national as well as international students. It is taught entirely in English. The teaching on this programme is strongly geared towards preparing students for research, and all four specialisations on the programme have links to strong research environments.

The program utilises competence on three campuses of the Swedish University of Agricultural Sciences located in Alnarp, Ultuna and Umeå. During the first year, all lectures are streamed live allowing to follow the courses from any of the three campuses.

During the second year, the students can specialise in either plant breeding and protection, abiotic and biotic interactions of plants or forest biotechnology. In fourth study track, students can decide to focus directly from the beginning on genetic and molecular plant biology.

Read more about SLU's new Master's programme here: