Gene regulation mechanism in drought-responsive grapevine leaves as revealed by transcriptomic analysis

The transcriptome of drought-stressed grapevine leaves was analyzed using RNA-sequencing (RNA-seq) technology and compared. In this experiment, 12,451 differentially expressed genes (DEGs) were recorded in response to drought by RNA-seq, which includes 7,983 up-regulated and 4,468 down-regulated transcripts, proposing that drought stress has induced/repressed many genes. Biological and physiological analysis revealed that drought has influenced the chlorophyll metabolism and photosynthetic activity in grapevine leaves. Besides, various defensive mechanism-related pathways including, reactive oxygen species (ROS), hormonal signal transduction, proline metabolism, biosynthesis of secondary metabolites, heat-shock proteins, and pathogenesis-related protein were also elucidated to understand drought-resistance related gene induction. Therefore, the transcriptional activity of ROS along with antioxidant enzymes, stress-related proteins, proline and secondary metabolites were strongly induced and played the tolerance-related role in response to drought stress. Moreover, an increased level of abscisic acid (ABA) and brassinosteroids (BRs) at physiological and transcriptomic level proved the fact that both hormones have a key defensive role against drought stress in grapevine leaves. In general, these findings will provide the drought tolerance-related gene information, which could be further used for developing drought-resistant grapevine varieties.