Transcriptomic responses of Saccharomyces cerevisiae and Hanseniaspora uvarum during separated co-fermentation

Hanseniaspora uvarum is a predominant yeast species in vineyards and some strains demonstrate oenological potential by enhancing the aroma complexity and reducing the content of volatile acid and ethanol in wine. H. uvarum kept in our lab could improve the flavor and quality of wine when co-fermented with Saccharomyces cerevisiae, but its growth was inhibited by S. cerevisiae. To investigate the interaction mechanisms of S. cerevisiae and H. uvarum, double-compartment fermentor with dialysis tube of 1000 kDa MWCO was selected for separated co-fermentation (SCF) in synthetic grape juice at 25℃ without agitation. Differentially expressed genes (DEGs) from S. cerevisiae and H. uvarum from SCF were analyzed using RNA-seq. H. uvarum exhibited a greater number of DEGs at both T1 (201) and T2 (444) compared to S. cerevisiae (T1: 158, T2: 294). Genes related to antioxidant and damage repair systems and glucose transportation and metabolism in S. cerevisiae were up-regulated at T1 and T2. Genes related to flocculation were up-regulated at T2. In contrast, H. uvarum from SCF down-regulated genes related to these pathways and up-regulated genes related to amino acid transportation and sulfate assimilation. These genes and pathway might potentially contribute to the interaction between S. cerevisiae and H. uvarum. Research results will provide a theoretical basis for yeast interaction mechanisms and research on other microbial interactions.