Integrated transcriptomic and proteomic analysis of the molecular mechanisms underlying hydrogen cyanamide–induced dormancy release in grape flower buds

• Integrated transcriptomic and proteomic analysis of grape flower bud dormancy. • Cyanamide regulates gene expression in energy metabolism, thereby promoting early germination of flower buds. • Cyanamide promotes protein and amino acid metabolism to break dormancy. • The weak correlation between transcriptome and proteome means that the development of buds is accompanied by post transcriptional regulation. • Cyanamide regulates the upregulation of gene and protein expression in grape buds to release dormancy. Low-temperature accumulation during winter is essential for dormancy release and germination of grape flower buds. In southern China, insufficient chilling accumulation is a common problem that leads to incomplete bud differentiation and highly variable germination rates, ultimately affecting grape yield and fruit quality. Hydrogen cyanamide (HC) is widely used to induce dormancy release in grape buds during winter, but the underlying molecular mechanisms remain unclear. In this study, bud structure and germination performance of five-year-old ‘Shuijing’ grapevines were investigated following treatment with 2.5 % HC. Subsequently, transcriptomic, proteomic, and integrated multi-omics analyses were performed. The results indicated that HC treatment reduced the time to germination and fruit ripening by 14 and 21 d, respectively. Transcriptome analysis identified 26,336 genes, of which 5258 were significantly differentially expressed genes (DEGs). HC regulated genes involved in the cell cycle, electron transport chain, and microtubule-based movement. It also induced the upregulation of genes associated with transferase activity, metal ion binding, ATP binding, protein binding, phosphorylation, and transcriptional regulation, particularly in DNA-templated processes. These genes were enriched in pathways related to energy, carbohydrate, and amino acid metabolisms. Proteomic analysis revealed 990 differentially expressed proteins (DEPs) that were predominantly enriched in the chloroplasts, cytoplasm, and nuclei. DEGs were involved in defense responses, detoxification of cellular oxidants, and oxidative stress responses. They also play key roles in amino acid biosynthesis, glycolysis/gluconeogenesis, carbon metabolism, and fructose and mannose metabolisms. Additionally, HC activated the pentose phosphate pathway, fatty acid biosynthesis, and arginine and proline metabolism. Integrated transcriptomic and proteomic analyses revealed that HC-induced dormancy release in ‘Shuijing’ grape buds was primarily regulated by photosynthesis, carbohydrate metabolism, fatty acid metabolism, and amino acid metabolism. Multiple pathways, including carbon metabolism, energy metabolism, peroxisome function, and photosynthesis, were identified to contribute to the dormancy release process. This study provides novel insights into the mechanisms underlying HC-induced dormancy release in grape flower buds from the transcriptomic and proteomic perspectives.