Early transcriptional response of Saccharomyces cerevisiae in mixed culture with Torulaspora delbrueckii in cherry wine

Mixed culture by Saccharomyces cerevisiae and Torulaspora delbrueckii has been proposed for the production of wine with improved aroma, but the yeast-yeast interactive mechanism still needs in-depth elucidation. This study compared the transcriptome responses of S. cerevisiae in single and mixed fermentations with T. delbrueckii, in the initial stages of cherry wine fermentation, in order to disclose the possible relationship between aroma synthesis and gene expression. Transcriptome profiling showed a total of 446 and 186 differentially expressed genes were detected in S. cerevisiae and T. delbrueckii, respectively, and several metabolic pathways such as glucose, lipid and amino acid metabolisms were observed with variations. For aroma, a total of 35 volatile compounds were identified by HS-GC-IMS, and mixed fermentation prominently enhanced the syntheses of most esters including propyl acetate, 2-methylpropyl acetate, isoamyl acetate and 2-methylbutyl acetate. By integrating the transcriptomic and volatile results, we propose that ILV5, BATs, PDCs, ADHs, ALDs, ACS1, ACC1 and ARO10 genes are possibly the decisive genes in S. cerevisiae, which showed significant variations following S. cerevisiae's adaptive responses in mixed culture and associated with the formation of certain aldehydes, alcohols and esters in cherry wine.