The use of autochthonous Saccharomyces cerevisiae strains as a strategy to enhance aroma variability and typicity of Savatiano wines; RNAseq-based transcriptome comparison of indigenous strains under winemaking conditions

The connection between wine microbiota and terroir has become increasingly significant in the wine industry in recent years. Indigenous yeasts have emerged as a valuable tool for imparting unique qualities to wine, enhancing the aroma characteristics specific to a given wine-producing region. This study aimed to isolate indigenous Saccharomyces cerevisiae strains from spontaneous fermentations and assess their impact on the fermentative performance, chemical composition, and wine aroma profiles, using two commercial strains serving as controls. Fermentation kinetics, organic acids, ethanol, and glycerol content were monitored daily using HPLC. The produced wines were evaluated for their organoleptic properties and underwent volatile compound profiling using GC–MS. Additionally, the gene transcription patterns of the isolated yeasts and their connection to the resulting oenological traits were further explored, employing RNAseq during fermentation. Our study revealed that native strains supported volatilome, promoted ester and terpene formation, enhanced fruity, floral, and sweet attributes, and contributed to a distinct wine aroma compared to the control ones. Of particular interest were the differences in organic acid metabolism and glycerol formation. Transcriptomes of the indigenous yeasts identified different genomic responses and explained the variations in metabolite production between strains. In conclusion, the data obtained highlights the different transcriptomic and metabolic profiles of the indigenous yeasts isolated during this study. Besides, the importance of understanding yeast genomics and metabolism to achieve promising sensory characteristics and unique wine styles was emphasized, and these insights could contribute to the development of new products while preserving the identity of a region.