title: The genetics and genomics of the drought response in Populus.
abstract: The genetic nature of tree adaptation to drought stress was examined by utilizing variation in the drought response of a full-sib second generation (F(2)) mapping population from a cross between Populus trichocarpa (93-968) and P. deltoides Bart (ILL-129) and known to be highly divergent for a vast range of phenotypic traits. We combined phenotyping, quantitative trait loci (QTL) analysis and microarray experiments to demonstrate that 'genetical genomics' can be used to provide information on adaptation at the species level. The grandparents and F(2) population were subjected to soil drying, and contrasting responses to drought across genotypes, including leaf coloration, expansion and abscission, were observed, and QTL for these traits mapped. A subset of extreme genotypes exhibiting extreme sensitivity and insensitivity to drought on the basis of leaf abscission were defined, and microarray experiments conducted on these genotypes and the grandparent species. The extreme genotype groups induced a different set of genes: 215 and 125 genes differed in their expression response between groups in control and drought, respectively, suggesting species adaptation at the gene expression level. Co-location of differentially expressed genes with drought-specific and drought-responsive QTLs was examined, and these may represent candidate genes contributing to the variation in drought response.
authors.affiliation: School of Biological Sciences, University of Southampton, Southampton SO16 7PX, UK.
authors.forename: Nathaniel Robert
authors.initials: NR
authors.lastname: Street
authors.forename: Oskar
authors.initials: O
authors.lastname: Skogström
authors.forename: Andreas
authors.initials: A
authors.lastname: Sjödin
authors.forename: James
authors.initials: J
authors.lastname: Tucker
authors.forename: Maricela
authors.initials: M
authors.lastname: Rodríguez-Acosta
authors.forename: Peter
authors.initials: P
authors.lastname: Nilsson
authors.forename: Stefan
authors.initials: S
authors.lastname: Jansson
authors.forename: Gail
authors.initials: G
authors.lastname: Taylor
mesh_terms: D004190:Disasters; D020224:Expressed Sequence Tags; D018745:Genome, Plant; D032107:Populus / Q000235:genetics*; D040641:Quantitative Trait Loci; D012333:RNA, Messenger / Q000235:genetics; D013045:Species Specificity
chemical_list: D012333:RNA, Messenger