Integration of E-nose, volatilomic profiling, and transcriptomics reveals the mechanisms aroma formation during the ripening process of blueberries

Blueberry aroma is a key determinant of fruit quality and market value. However, the mechanisms underlying its formation during ripening remain poorly understood. This study utilized the highbush blueberry cultivar 'Legacy' and employed an integrated approach combining E-nose, GC-MS, GC-IMS, and transcriptomics to systematically analyze the formation and changes in VOCs as well as the underlying molecular mechanisms throughout fruit ripening. The results revealed that during the entire fruit ripening process, VOCs were predominantly composed of alcohols, aldehydes, and terpenoids. Key compounds, including hexanol, linalool and geraniol, progressively accumulated. Furthermore, the combination of GC-MS and GC-IMS provided a more comprehensive profile of the volatile composition in blueberry fruit. Transcriptomic analysis further elucidated its metabolic regulatory mechanisms: 1) Terpenoid biosynthesis is co-regulated by the MAV and MEP pathways, with the MEP pathway playing a dominant role in monoterpene biosynthesis; 2) Fatty acid metabolism generates C6 aldehydes via LOX2S, while upregulation of ADH gene expression significantly enhances the conversion of aldehydes to alcohols. This study provides valuable theoretical foundations for flavor development during blueberry ripening.