Vineyard floor mulching and removal modulates Marselan aroma formation in association with microclimate-dependent metabolic and transcriptomic regulation

Vineyard geotextile mulching is widely used to control weeds and conserve soil moisture in water-limited vineyards, but its effects on berry aroma formation and underlying transcriptomic regulation remain unclear. Here, whole-field mulching was applied from anthesis and removed at two key phenological stages across three vintages (2015-2017). Soil properties, grape volatile profiles, and transcriptomic responses were analyzed. Mulching promoted downward nutrient movement and upregulated genes involved in photosynthesis, carbon metabolism, terpenoid and norisoprenoid biosynthesis, enhancing volatile accumulation particularly in 2015 under higher radiation and lower rainfall conditions. Mulching removal around veraison resulted in higher volatile accumulation than either full-season mulching or no mulching. Co-expression network analysis identified modules enriched in light signaling, transport, and transcription, with bHLH075, bZIP05, WRKY21, and YABBY5 as potential regulators. In summary, this study elucidates the dynamic aroma-environment interactions and molecular responses in grape berries, providing insights for optimizing vineyard management to enhance grape and wine aroma quality in semi-arid regions.