Multi-omics analysis of the regulatory network in winter buds of 'Cabernet Sauvignon' grapevine from dormancy to bud break.

Winter dormancy and bud break are crucial to the viability, adaptability and yield of fruit trees, but not all metabolic activities or regulatory factors involved in maintaining and breaking dormancy are known. Here, winter buds, spanning from natural dormancy to bud break, were collected from 'Cabernet Sauvignon' grapevines maintained outdoors or forced indoors. The transcriptomes, proteomes and plant hormone contents were analysed across several bud stages. The winter buds presented three main stages, dormancy, dormancy release and bud development, whether grown in or outdoors. Weighted Correlation Network Analysis (WGCNA) and Gene Ontology (GO) analysis of the omics data revealed that the different stages were enriched for different biological processes. Analysis of the differentially expressed genes (DEGs) identified seven candidate genes that may affect grape dormancy and bud break. Transient transformation of these seven genes showed that VvDOGL4, VvAGL65 and VvMARD could promote maintenance of winter bud dormancy in grapevine. Subcellular localization showed that these three proteins all located to the nucleus, and yeast two-hybrid screening showed that they may interact with proteins related to plant hormone signal transduction, respiration, energy metabolism and transcription regulation to affect winter bud break in grapevine. Overall, these findings contribute to a better understanding of the regulatory dynamics of bud dormancy in a perennial fruit crop and lay a foundation for exploring key genes and regulatory mechanisms that can be manipulated to improve fruit quality and yields as the global climate shifts growing regions.