INUPRAG is a virtual “European Open Laboratory” that is based on a trilateral agreement between the Umeå Plant Science Centre (UPSC, Sweden), the National Institute for Agricultural Research (INRA, France) and the Centre for Research in Agricultural Genomics (CRAG, Spain). The goal is to bring together researchers for joint research projects to facilitate the transfer of knowledge and tools, developed with plant model species like Arabidopsis and Poplar, to crops and trees.
To foster the collaboration, the Kempe Foundations finances six post-doctoral fellowships that were granted to six collaborative projects between UPSC research groups and INRA or CRAG research groups. The objective is to promote the training of young scientists through regular exchanges between the partner laboratories and to enable them to develop their networks. The recruited post-doctoral fellows will be recruited in Sweden but will be seconded during three months to one year in the French or Spanish partner laboratory.
Project 1: Interactions between Plastid and Light Signalling Pathways
Project leaders: Åsa Strand (UPSC) & Elena Monte (CRAG )
In this collaborative project between Umeå Plant Science Centre, UPSC and Center for Research in Agricultural Genomics, CRAG, we will define the interactions between plastid and light signalling pathways required for the development of photosynthetically functional chloroplasts. Light and plastid signals regulate expression of the same group of photosynthesis-related genes and it has been reported that light and plastid signals also are mediated by cis elements found in close proximity. This suggests a close interaction between these two signalling pathways that we have recently begun to untangle. In detail the candidate will address the molecular function of GUN1 in the chloroplasts and the mechanism behind interaction of GUN1 with the transcription factor GLK1. Genetics, molecular biology, biochemistry and cell biology will be used and in planta experimental systems will be combined with an Arabidopsis cell line.
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Project 2: Regulation of the Master Floral Regulator LEAFY by Ubiquitination through the E3 Ligases UFO and BOP2
Project leaders: Markus Schmid (UPSC), Ove Nilsson (UPSC) & François Parcy (INRA, Grenoble)
In this collaborative project between Umeå Plant Science Centre (UPSC) and the National Institute for Agricultural Research (INRA), we will investigate how the E3 ubiqutin ligases UFO and BOPs modulate the activity of the floral master regulator LFY in Arabidopsis thaliana. We will perform ChIP-seq and RNA-seq for UFO and BOP reporter lines in both wildtype and lfy mutant background. These experiments will help to i) identify UFO and BOP target genes, ii) evaluate whether LFY is required for UFO and BOP DNA binding, and iii) study their effect on gene expression. These genomic experiments will be complemented by detailed in vitro analyses using a variety of biochemical approaches. In summary, the proposed experiments will help to clarify how the spatially restricted activity of cofactors helps to modulate the activity of the floral master regulator LFY in emerging flower primordia.
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Project 3: An evo-devo approach to elucidate the role of PIRIN proteins during non-cell autonomous lignification
Project leaders: Hannele Tuominen (UPSC) and Richard Sibout (INRA, Nantes)
Plant xylem tissues consist of vessel elements and fibers which deposit secondary cell walls as a part of their maturation. Lignin is a cell wall component that reinforces the walls and confers a hydrophobic barrier which is crucial for water transport in the xylem vessels. We have shown that lignification is partially a non-cell-autonomous process in which the lignin monomers are supplied to the lignifying cells by their neighbouring cells (Pesquet et al. 2013, Plant Cell 25:1314-28). We have also identified parts of the molecular machinery that mediate the non-cell autonomous lignification of the xylem vessel elements. The post doc project will build on these results and focus on the role of a nuclear, cupin-domain containing family of proteins in regulation of lignification with the help of various molecular, genetic and physiological methods.
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Postdoctoral project 4: Unravelling cluster root emergence in white lupin
Project leaders: Stéphanie Robert (UPSC) & Benjamin Péret (INRA, Montpellier)
Plants mostly adapt thanks to the formation and outgrowth of roots, determining the root system architecture (RSA). Morphological changes such as root development, mediated via cell division, differentiation and elongation, are complex processes involving remodelling of the wall surrounding the cell. The white lupin is the only cultivated species forming cluster roots, structures made of hundreds of rootlets that are produced almost synchronously as an adaptation to low phosphate. Interestingly, these structures are a very efficient developmental and physiological adaptation to poor soils but their mode of development is poorly described. Most importantly, these numerous organs have to cross several layers of cellular tissues (endodermis, cortex and epidermis) in a process called emergence. Previous work in the model plant Arabidopsis thaliana has identified a mechanism involving auxin transport and response during root emergence but Arabidopsis has a very limited number of outer cell layers and only one primordium emerges at a given time. How white lupin rootlets manage to cross these barriers without damaging the outer tissues is currently unknown and probably involves mechanical remodelling. In this project, we will characterize rootlet emergence in white lupin by taking advantage of constitutive cluster root mutants identified by the Peret’s lab (Montpellier, France). This molecular characterization will involve studying marker gene expression patterns during rootlet development, expression analysis and transfer between the two plant models. We will validate the existence of an auxin-based emergence mechanism in species outside of Arabidopsis, ii) elucidate how this system is built in a multilayer organ and iii) determine the changes in cell wall properties occurring during emergence and their relation to auxin accumulation.
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Project 5: Cell wall mediated control of differential cell elongation in Arabidopsis hook Development
Project leaders: Rishikesh Bhalerao (UPSC) and Olivier Hamant (ENS, INRA, Lyon)
The postdoctoral fellow will work within this project on the role of cell wall mechanics in regulation of differential cell elongation in the model plant Arabidopsis thaliana. It is a joint project between the lab of Rishi Bhalerao at UPSC in Umeå, Sweden and Olivier Hamant at ENS Lyon in France. The project builds on previous work from both labs: Hamant et al Science (2008), Uyttewaal et al., Cell (2012), Hervieux et al., Curr. Biol. (2016, 2017), Gendre et al PNAS (2011), Boutte et al PNAS (2013) and Gendre et al Plant Cell (2013), Jonsson et al (2017). We have isolated several mutants with altered secretion and cell wall composition that alter differential cell elongation in the model plant Arabidopsis. The project aims to characterise these mutants using cell biological and biochemical and genetic approaches.
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Project 6: Enabling scale-up of somatic embryogenesis (SE) plant production by physiological analysis of embryos processed in bioreactors and the R&D SE System for harvest
Project leaders: Ulrika Egertsdotter (UPSC) and Marie-Anne Lelu-Walter (INRA, Orleans)
The project will analyse biochemical compositions of different somatic embryo types in spruce and larch. Key findings on metabolites related to the physiological status of germination-permissive embryo types that coincide in Norway spruce and larch would indicate underlying processes generic for the conifer SE process. Such finding will help improve SE protocols and provide candidates for marker development to enable early selection of embryos capable of germinating and forming plants.