Effect of canopy height and tree shape on anthocyanins accumulation in wine grape.

Flavonoid synthesis and metabolism are strongly influenced by environmental factors such as temperature and light. To delve deeper into the metabolic differences and regulatory mechanisms underlying anthocyanin production in wine grape berries, we adjusted the canopy height. We hypothesized that increasing canopy height would enhance anthocyanin accumulation in grape berries by upregulating the expression of key genes in the flavonoid biosynthesis pathway. Using integrated metabolomic and transcriptomic analyses, we identified increased canopy height enhanced anthocyanin content in wine grape berries by more than 2.1-fold. Twenty-six differentially expressed genes linked to anthocyanin production were identified, which are key regulators of flavonoid synthesis and metabolism. Eight candidate genes were validated via RT-qPCR, confirming the transcriptomic findings. Our results demonstrate that there were differences in anthocyanin accumulation among different varieties, the increased canopy height promotes anthocyanin biosynthesis and accumulation in grape berries. This study validates our initial hypothesis, demonstrating that canopy management serves as an effective practice to promote berry coloration. The identified candidate genes provide specific genetic targets for breeding programs aimed at improving anthocyanin content in wine grapes.