Abstract: To investigate the effects of cultivation practices on microbial communities and volatile flavor compounds during spontaneous fermentation of Marselan wine, this study used Marselan grapes from conventional (CV), natural farming (NF), and biodynamic (BD) cultivation systems as raw materials for winemaking. High-throughput sequencing and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) were employed to analyze the composition and successional patterns of microbial communities and volatile flavor compounds during fermentation. Redundancy analysis (RDA) and Spearman correlation analysis were used to explore the relationships between indigenous core microorganisms and volatile flavor compounds. The results indicated that BD wine samples exhibited higher overall microbial diversity than NF and CV samples. The dominant fungal genera in the early fermentation stage were Alternaria, Cladosporium, and Botrytis, while Saccharomyces and Hanseniaspora became dominant as fermentation progressed. The dominant bacterial genera included Cupriavidus, Tatumella, Lactobacillus, Massilia, Sphingomonas, and Pseudomonas. Cupriavidus and Pseudomonas were dominant in the CV mode, while Tatumella and Lactobacillus exhibited the highest relative abundance in the BD mode. The variety and concentration of flavor compounds were the highest at the end of fermentation, with significant differences among modes. RDA results indicated that for the BD mode, Tatumella, Saccharomyces, and Hanseniaspora were positively correlated with 1-pentanol and acetaldehyde. In the NF mode, Lactobacillus was positively correlated with hexanal, and linalool, while Hanseniaspora was positively correlated with acetaldehyde but negatively correlated with linalool. In the CV mode, decanal, dodecanal, and other aldehydes were positively correlated with Cupriavidus and negatively correlated with Botrytis and Cladosporium. Spearman analysis further confirmed that Saccharomyces showed strong positive correlations with most aroma compounds, while Botrytis and Cladosporium exhibited negative correlations with certain alcohols. This study provides theoretical support for elucidating how cultivation practices influence the aroma quality of wine by shaping the microbial community.

Key words: high-throughput sequencing; cultivation patterns; spontaneous fermentation; volatile flavor compounds