Genome-wide identification, annotation and expression profile analysis of SnRK2 gene family in grapevine

Background and Aims: Protein kinases are widely involved in the response in plants to external environment stress signals. Sucrose non-fermenting 1-related protein kinase 2 ( SnRK2) is an important class of plant-specific protein kinases that plays a crucial role in abscisic acid responses and abiotic stresses across some model plant species. Genome-wide annotation, however, and specific expression patterns of SnRK2s in grapevine remain unclear. Methods and Results: From a genome-wide survey of grapevine, we identified eight VviSnRK2 genes through phylogenetic and local BLAST methods and various bioinformatics analyses. Phylogenetic analysis indicated that these VviSnRK2s could be classified into three subgroups as found in Arabidopsis. Comparison of the structure of the genes with those of Arabidopsis suggests that intron length may be a special evolutionary imprint of the SnRK2 gene family in grapevine. Sequence alignment and structural annotation provided an overview of variations that may contribute to functional divergence from Arabidopsis SnRK2s. Expressional analyses based on public microarray data and quantitative real-time polymerase chain reaction and co-expression network analyses suggest both conserved and variant biological functions exist in SnRK2s across different species. Conclusions: Our thorough analysis of the SnRK2 gene family in the grapevine genome revealed functional conservation and diversity synchronously existed in grapevine SnRK2 gene family. Significance of the Study: Our research provides a comprehensive overview of both the expression pattern and functional diversity of the grapevine SnRK2 gene family, which will facilitate the future functional characterisation of individual VviSnRK2 genes.