From Soil to Wine: Influence of Vegetative Covers on Microbial Communities and Fermentative Dynamics in Cabernet Sauvignon

The implementation of vegetative cover crops in vineyards is a sustainable alternative to chemical weed control, potentially influencing both soil fertility and grape-associated microbiota. This study evaluated the impact of six groundcover management strategies under vines-white clover (<i>Trifolium repens</i>), red clover (<i>Trifolium pratense</i>), burr medic (<i>Medicago polymorpha</i>), lupine (<i>Lupinus albus</i>), spontaneous weeds, and an herbicide-treated control-on the microbial dynamics and physicochemical properties of <i>Cabernet Sauvignon</i> must and wine from the Maipo Valley, Chile. Amplicon sequencing of bacterial (16S rRNA) and fungal (ITS) communities was combined with spontaneous fermentation trials and chemical analyses of must and wine. Fungal and bacterial communities on grape surfaces were dominated by <i>Ascomycota</i> and <i>Proteobacteria</i>, respectively, with no significant compositional differences among treatments. During fermentation, <i>Metschnikowia</i> and <i>Tatumella</i> were the most abundant non-<i>Saccharomyces</i> and bacterial genera, respectively, showing dynamic shifts across fermentation stages. Legume-based covers, particularly red clover, increased wine total acidity and polyphenol index while reducing pH. Correlation analyses revealed associations between specific microbial taxa (<i>Metschnikowia</i>, <i>Cohnella</i>, <i>Saliterribacillus</i>) and key enological parameters. Overall, these findings demonstrate that leguminous cover crops subtly modulate vineyard microbial ecology and fermentation outcomes, offering an environmentally sustainable pathway to enhance enological differentiation in semi-arid viticultural regions.