Grapevine bZIP transcription factor bZIP45 regulates and confers drought tolerance in .

Drought is a severe environmental condition that restricts the vegetative growth and reduces the yield of grapevine (). However, the mechanisms underlying grapevine response and adaptation to drought stress remain unclear. In the present study, we characterized an ANNEXIN gene, , which plays a positive role in the drought stress response. The results indicated that was significantly induced by osmotic stress. Expression of in enhanced osmotic and drought tolerance through modulating the level of MDA, HO, and O at the seedling stage, implying that might be involved in the process of ROS homeostasis under drought or osmotic stress conditions. Moreover, we used yeast one-hybridization and chromatin immunoprecipitation assays to show that VvbZIP45 could regulate 1 expression by directly binding to the promoter region of 1 in response to drought stress. We also generated transgenic that constitutively expressed the gene (35S::) and further produced ::GUS/35S:: plants crossing. The genetic analysis results subsequently indicated that VvbZIP45 could enhance GUS expression under drought stress. Our findings suggest that VvbZIP45 may modulate expression in response to drought stress and reduce the impact of drought on fruit quality and yield.