Genome-wide association mapping and transcriptomic analysis reveal key drought-responding genes in barley seedlings

Drought stress is a major abiotic factor restricting crop production. frequently suffers from drought stress as it is mainly planted in the harsh environments. Little research on the identification of drought-tolerant loci or genes of barley has been performed up to date. Here, we determined the phenotypic variation of drought tolerance in a barley population from the International Barley Core Selected Collection (BCS). Under drought stress, shoot water content showed the distinct difference among barley genotypes and the maximum consistency for a given genotype under the two planting conditions. Twenty significant SNPs (P < 10−3) and 41 candidate genes were identified by genome-wide association study (GWAS)on the examined barley accessions. Furthermore, transcriptomic analysis (RNA-Seq) identified 2030 and 1947 differentially expression genes (DEGs) in the leaves of a drought-sensitive genotype BCS8 and a tolerant genotype BS24, respectively, and they are mainly involved in water deficit processes in GO analysis and metabolic pathways in KEGG analysis. Finally, seven DEGs were confirmed by qRT-PCR as drought-responding genes, including WRKY, NPF and FLA.