Transcriptomic and ecophysiological analyses revealed contrasted soybean mineral nutrition under individual or combined heat and water stresses

book of abstracts pages 183-184International audienceObjectives, Description, Main Results & ConclusionsIn a context of climate change, with more frequent drought events and heatwaves, it is predicted that soybean yields will drastically decrease in the near future. Soybean being the most widely grown legume crop in the world, there is an urgent need to improve its ability to sustain its growth under such conditions in order to guarantee high levels of productivity. The aim of this study was to explore the influence of heat and/or water stress on soybean growth and its water and mineral nutritions. Two soybean genotypes, displaying contrasted root architectures during their vegetative stage were grown under controlled conditions in the 4PMI high-throughput phenotyping platform where either optimal conditions, or heatwaves, or water stress, or both heatwaves and water stress were applied. Plants were characterized for their morphology, their water uptake, the mineral composition of their tissues and their root transcriptome (RNA-seq analyses). An ecophysiological structure-function framework, enabled us to link structural variables (leaf area, root architecture, biomass, etc.) to functional variables (water use efficiency, element uptake and use efficiencies…) to understand the interactions between water and element fluxes at the whole plant level, and to quantify the overall tolerance of plants to each stress. Under combined stress conditions, one genotype appeared more susceptible. The genotypic difference was due to functional changes, particularly for water uptake and to differences in the content of certain elements in the roots (magnesium and calcium with their role in osmoregulation, and nickel, sulfur or sodium). This cross-analysis of the plant ionome, root architectural traits and root transcriptome under different stresses, is offering us new insights into soybean adaptation to climate change