Microbiota succession from grape epidermis to wine and its impact on volatile compounds in spontaneous and inoculated fermentation of Marselan wine from Yanqi Basin, Xinjiang

Marselan wine is a highly popular red wine variety. However, the microbial terroir and its impact on volatile profiles during industrial-scale spontaneous (SF) and inoculated (IF) fermentation of Marselan wine in China's core wine regions remain poorly characterized. This study investigated microbial community dynamics from Marselan grape epidermis to fermentation in Yanqi Basin, Xinjiang, and compared volatile compound profiles in IF and SF as well as analyzed their correlations. The results revealed that microbial community composition and structure shifted during the growing stage and fermentation. Bacteria genera Achromobacter , Pedobacter, Lactobacillus and fungi Cladosporium , Alternaria and Filobasidium , dominated the grape epidermis. The bacterial community was more diverse during SF, and yielded a greater variety of volatile compounds in SF (65) than in IF (47). However, IF produced a higher volatile compound content (341578.53 μg/L) than SF (301889.28 μg/L). β-Damascenone exhibited the highest OAVs, with a higher level in SF (194.6) than in IF (184.4). SF uniquely produced ionone, while IF uniquely produced linalool. Key indigenous microorganisms contributed to volatile substances included Saccharomyces , Aspergillus , Achromobacter , Lactobacillus , Leuconostoc , Methylobacterium-Methylorubrum , Gluconobacter , Acinetobacter , Vogesella , Talaromyces and Cladosporium. This work provides insights into the microbial terroir and aroma formation of Marselan wine in Xinjiang, establishing a scientific basis for harnessing indigenous microbiota to enhance wine typicity and quality in China's wine industry. • Achromobacter , Cladosporium , Filobasidium , and Alternaria predominated on epidermis. • SF produced a greater variety of volatile compounds than IF (65 vs. 47 compounds). • IF produced a higher volatile compound content than SF (341578.53 μg/L vs. 301889.28 μg/L). • β-Damascenone exhibited the highest OAVs, with higher levels in SF (194.6) than in IF (184.4). • Several key indigenous microorganisms were correlated with volatile compounds formation.