Insights into the organic acid and flavonoid metabolisms in moderately withered blueberries based on metabolomics and transcriptomics

• Moderate withering decreased aliphatic organic acids in blueberries and wines. • Moderate withering favored phenolic acid and flavonoid synthesis in blueberries. • Key genes responsible for metabolite changes in withered berries were identified. • Moderate withering decreased acids but increased anthocyanins in blueberry wines. This study employed integrated metabolomic and transcriptomic analyses to investigate the impacts of moderate withering (approximately 30% weight loss) on organic acid and flavonoid accumulation in blueberries and the resultant blueberry wines. Moderate withering led to decreases in aliphatic organic acids but increases in phenolic acids and flavonoids in blueberries. The decrease in malate could be linked to the downregulated VcMDH and VcDTC , and the decrease in citrate and 2-oxoglutarate could be a consequence of γ - aminobutyric acid shunt activation. The increases of phenolic acids were associated with upregulated VcCAD and VcPOD in withered blueberries. Additionally, moderate withering upregulated the expression of VcLAR and VcUFGT , promoting flavonoid accumulation. In blueberry wines, moderate withering decreased total aliphatic organic acid content but increased anthocyanin content, consistent with the findings in blueberries. Overall, this study provided references for applying moderate withering in blueberry winemaking, contributing to modulating acidity and enriching phenolic substances.