Modeling budbreak precocity in grapevine: insights from comparative gene expression analysis in single-node cuttings

Main conclusion: Single-node cuttings are an effective tool for the study of grapevine’s budbreak timing and cultivar-specific regulation of shared molecular/physiological processes, ABA and VviFT key role. Abstract: Global warming is known to accelerate buds’ phenological development and increase spring frost damage risk in several areas of the world. All studies in this area involve monitoring this intricate process, which is in the field time-consuming and challenging due to the considerable influence of environmental factors. This work explores the possibility of studying dormancy in grapevine by means of single-node cuttings of early- and late-bud break model cultivars Chardonnay and Cabernet Sauvignon. Both visual phenotyping and differential thermal analysis confirmed the expected different pace of dormancy release in the two varieties. In addition, specific Gene Ontology (GO) categories with similar but shifted expression patterns between early-bud break Chardonnay and late-budbreak Cabernet Sauvignon have been identified, suggesting cultivar-specific regulation of shared molecular processes. Notably, the VviFT gene aligns with this timing shift, indicating its potential role in budbreak. We further confirm the importance of ABA inhibition in growth resumption and identify genes like VviSVP2 and VviDRM1 as possible dormancy release repressors. Our study enhances the understanding of the molecular network underpinning dormancy in grapevine buds and provides a robust framework for future research in this area.