Abstract:

Diacylglycerol kinase（DGK）is a key signaling enzyme that induces the synthesis of phosphatidic acid（PA）under adverse stress and plays an important regulatory role in the process of cellular signal transduction. To systematically analyze the DGK family gene members in grapes and conduct biological function research，based on the grape genome database，searched for and identified the DGK gene family members in grapes，and conducted analyses on their phylogenetic evolution，physicochemical properties，gene structure，protein and promoter sequences，and gene expression levels. In addition，VvDGK1 was genetically transformed into Arabidopsis thaliana and subjected to salt stress treatment，and the interacting proteins of VvDGK1 were screened and identified. The results showed that a total of five DGK family members were identified in the grape genome database. Among them，VvDGK1 and VvDGK2 belong to ClusterⅠ，VvDGK3 to ClusterⅡ，and VvDGK4 and VvDGK5 to Cluster Ⅲ. Systematic evolution and collinearity analysis revealed that the five VvDGKs in grapes have a relatively high homology with the DGK genes in apples，and the collinearity relationship between VvDGK1 and MdDGK3，MdDGK7，and AtDGK1 is the strongest. The promoter region of the VvDGKs gene contains a large number of cis-acting elements related to growth and development，plant hormones，and responses to adverse stress. The VvDGK gene has a relatively high expression level in stems and leaves，but a relatively low expression level in roots，flowers and fruits，showing obvious tissue specificity. The VvDGK gene shows different expression patterns under stress treatments such as drought，salt，and abscisic acid. Among them，VvDGK1 gene expression was significantly induced under different stress treatments. Overexpression of VvDGK1 in Arabidopsis revealed that the transformed strain enhanced resistance to salt stress，slowed the decline of the maximum photochemical efficiency of leaf photosystemⅡ（F_v/F_m）and the degradation of chlorophyll under stress，reduced the accumulation of reactive oxygen species under stress，and increased the activity of antioxidant enzymes（such as CAT，POD and APX）. The yeast two-hybrid system screened out VvFd and VvRCA，which can interact with VvDGK1. The bimolecular fluorescent complimentary（BiFC）further verified the in vivo interaction between VvDGK1 and VvFd. It is speculated that VvDGK1 participates in signal transduction under salt stress by influencing photosynthesis through interaction with VvFd and VvRCA.

Key words: grapevine, diacylglycerol kinase, VvDGK1, salt stress, protein-protein interaction