VvWNK10 phosphorylation enhances stabilization of VvD14 protein activates SL signaling to confer drought resistance in grapevine

Abstract

Drought stress seriously affects the growth and development of plants. Strigolactone (SL), as a new type of plant hormone, plays an important role in the plant response to drought stress. In this study, the key gene VvD14 of strigolactone signal transduction was cloned and its function was verified. In Arabidopsis thaliana, overexpression of VvD14 conferred higher drought resistance. Arabidopsis thaliana overexpressing VvD14 had higher antioxidant enzyme activities under drought stress. Overexpression of VvD14 enhanced drought resistance and endogenous SL content in grape callus. Moreover, VvD14-OE transgenic callus had higher antioxidant enzyme activities and anthocyanin content. Under drought stress, overexpression of VvD14 enhanced the expression of drought stress-related genes and anthocyanin-related genes in callus. The transgenic VvD14 grape seedlings showed significantly improved drought tolerance compared with WT, as evidenced by higher activities of CAT and SOD. Additionally, VvWNK10-overexpressing grape callus had higher fresh weight and antioxidant enzyme activity under drought stress, indicating improved drought tolerance. In addition, it was found that VvD14 interacts with serine/threonine protein kinase VvWNK10, and VvWNK10 can phosphorylate VvD14 to enhance its protein stability. This is the first discovery of a serine/threonine protein kinase (VvWNK10) that interacts with VvD14 and affects its protein stability. Thus, our results suggest that VvWNK10 enhances drought resistance in grapevine by phosphorylating VvD14, thereby regulating the SL signaling pathway.