Transcriptome profiling disclosed the effect of single and combined drought and heat stress on reprogramming of genes expression in barley flag leaf

This study was aimed at deciphering the impact of drought and heat on genome-wide gene expression in flag leaf of barley. We employed high-throughput sequencing of mRNA to identify genes that are associated with response to drought or heat and to their combination. Our study demonstrated that under combined stress, drought was the dominant factor affecting genes expression. It was also confirmed for phenotypic traits and chlorophyll fluorescence parameters. Drought- and heat-responsive genes were associated majorly with photosynthesis, abscisic acid signaling and lipids transport. Dehydrin encoding genes were found to be universal stress-responsive genes. Stress-induced genes specific to the flag leaf size were also found. This research provided novel insight into molecular mechanisms of barley flag leaf that determine drought and heat response, also during their co-occurrence.