Diversity of volatile phenols and their newly identified precursors during different grape species development

Grape-derived volatile phenols significantly contribute to wine aroma, yet their developmental dynamics and species-specific regulation in grapes remain poorly understood. This study monitored 18 volatile phenols and identified 20 glycosidic precursors during berry development in three East Asian grape species (<i>Vitis davidii</i>, <i>V. quinquangularis</i>, <i>V. amurensis</i>) and <i>V. vinifera</i> cv. Cabernet Sauvignon from two regions (Ningxia and Changli). Using a pseudo-targeted metabolomic approach coupled with UHPLC-qTOF-MS/MS, we profiled precursors of <i>m/p</i>-cresol, guaiacol, 4-vinyl-phenol, 4-vinyl-guaiacol, isoeugenol, and coniferaldehyde. Time-series analysis revealed markedly distinct accumulation patterns: East Asian species showed progressive accumulation of volatile phenols and higher precursor concentrations than <i>V. vinifera</i>, with <i>V. davidii</i> exhibiting the highest levels. Cabernet Sauvignon displayed contrasting regional patterns-gradual accumulation in Changli versus an early peak followed by decline in Ningxia. Six precursors were exclusive to East Asian species, indicating species-specific glycosyltransferase activities and serving as potential markers for predicting varietal identity. Widespread precursors (e.g., glycosidic <i>m/p</i>-cresol, isoeugenol, and coniferaldehyde) showed strong positive correlations with their volatile phenols, demonstrating predictive potential. Collectively, these results provide a systematic analysis of the expression of volatile phenols and their precursors and reveal pronounced metabolic differences between East Asian and <i>V. vinifera</i> grapes, as well as between growing regions. This knowledge provides actionable guidance for vineyard management, varietal selection, and wine style development.