Vitis vinifera bZIP14 functions as a transcriptional activator and enhances drought stress resistance via suppression of reactive oxygen species

Abstract

Background: Drought stress affects grapevine growth and development and reduces berry yield and quality. Identifying genes that are involved in the plant response to drought stress will enable the development of new grape strains that are tolerant to drought. Objective: We cloned the VvibZIP14 gene from Vitis vinifera and analyzed its role in drought resistance. Methods: Gene expression was analyzed by quantitative real-time PCR. Subcellular localization was assessed with a transient expression assay. The transactivation activity of the protein was evaluated in yeast. The physiologic role of VvibZIP14 was analyzed by overexpressing VvibZIP14 in Arabidopsis following drought stress. Hydrogen peroxide accumulation in Arabidopsis was visualized by diaminobenzidine staining. Results: Drought stress caused the accumulation of VvibZIP14, which was localized in the nucleus and had transcriptional activity. Transgenic plants showed improved resistance to drought stress and reduced electrolyte leakage compared to plants overexpressing empty vector, whereas chlorophyll content, photosystem II maximal photochemical efficiency, and net photosynthetic rate were higher. Catalase, peroxidase, and superoxide dismutase activities were also increased in VvibZIP14-overexpressing plants subjected to drought stress. Conclusions: VvibZIP14 functions as a transcription factor that confers resistance to drought stress in grape by enhancing the antioxidant response.