xyleme-Molecular bases of acclimation and adaptation to water deficit in poplar.

affy_popsec_orleans_poplar - xyleme - This project aims to identify candidate genes for water deficit acclimation and/or adaptation in a tree species: poplar. Due to compelling evidence that transcriptional regulation plays a major role in regulating many biological processes, we will look for genes and gene expression networks related to drought stress. We intend to analyse the transcriptome in two poplar genotypes of contrasted tolerance to water deficit, at various stages and intensities of stress and simultaneously in whole xylem and cambial zone from young trees. The co-analysis of two genotypes of contrasted tolerance to water deficit should allow to better discriminating genes presenting a potential adaptative character from genes responding passively to the constraint. The consideration of both whole xylem and cambial zone will enable us to discriminate between regulations events originating from very young xylem cells undergoing their first steps of xylem differentiation (cambial zone) compared to whole xylem sample enriched in more differentiated xylem cells and parenchyma ray cells.-Two poplar clones, named Soligo (S) and Carpaccio (C) were submitted to 4 treatments: non-stressed control, severe-drought stress, mild-drought stress and early-drought stress. Two pools of 2 or 3 trees were considered as biological replicates. Two different samples were collected on each individual tree: whole stem xylem (X) and cambial zone plus very young expanding xylem (Y). Total RNAs were extracted from each tree and assemble in pool of 3 or 2 individuals using equimolar ratio for each X and for Y. One affymetrix slide corresponds to one pooled RNA sample (X or Y). A total number of slides : 4 treatments x 2 clones x 2 tissues x 2 biological replicates (pool) = 32 slides, will be done.

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