Saccharomyces cerevisiae, an essential player in alcoholic fermentation during winemaking, is rarely found in intact grapes. Although grape-skin environment is unsuitable forS. cerevisiae’s stable residence, Saccharomycetaceae-family fermentative yeasts can increase population on grape berries after colonization during raisin production. Here, we addressed adaptation ofS. cerevisiaeto grape-skin ecosystem. The yeast-like fungusAureobasidium pullulans, a major grape-skin resident, exhibited broad spectrum assimilation of plant-derived carbon sources, including ω-hydroxy fatty acid, arising from degradation of plant cuticles. In fact,A. pullulansencoded and secreted possible cutinase-like esterase for cuticle degradation. When intact grape berries were used as a sole carbon source, such grape-skin associated fungi increased the accessibility to fermentable sugars by degrading and assimilating the plant cell wall and cuticle compounds. Their ability seems also helpful forS. cerevisiaeto obtain energy through alcoholic fermentation. Thus, degradation and utilization of grape-skin materials by resident microbiota may account for their residence on grape-skin andS. cerevisiae’s possible commensal behaviors. Conclusively, this study focused on the symbiosis between grape-skin microbiota andS. cerevisiaefrom the perspective of winemaking origin. Such plant–microbe symbiotic interaction may be a prerequisite for triggering spontaneous food fermentation.