AUTHOR=Lin Yuan , Zhang Na , Lin Yonghong , Gao Yinhao , Li Hongxing , Zhou Cuixia , Meng Wu , Qin Weishuai 

TITLE=Transcriptomic and metabolomic correlation analysis: effect of initial SO2 addition on higher alcohol synthesis in Saccharomyces cerevisiae and identification of key regulatory genes

JOURNAL=Frontiers in Microbiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1394880

DOI=10.3389/fmicb.2024.1394880

ISSN=1664-302X

ABSTRACT=<sec id="sec1"><title>Introduction</title><p>Higher alcohols are volatile compounds produced during alcoholic fermentation that affect the quality and safety of the final product. This study used a correlation analysis of transcriptomics and metabolomics to study the impact of the initial addition of SO<sub>2</sub> (30, 60, and 90 mg/L) on the synthesis of higher alcohols in <italic>Saccharomyces cerevisiae</italic> EC1118a and to identify key genes and metabolic pathways involved in their metabolism.</p></sec><sec id="sec2"><title>Methods</title><p>Transcriptomics and metabolomics correlation analyses were performed and differentially expressed genes (DEGs) and differential metabolites were identified. Single-gene knockouts for targeting genes of important pathways were generated to study the roles of key genes involved in the regulation of higher alcohol production.</p></sec><sec id="sec3"><title>Results</title><p>We found that, as the SO<sub>2</sub> concentration increased, the production of total higher alcohols showed an overall trend of first increasing and then decreasing. Multi-omics correlation analysis revealed that the addition of SO<sub>2</sub> affected carbon metabolism (ko01200), pyruvate metabolism (ko00620), glycolysis/gluconeogenesis (ko00010), the pentose phosphate pathway (ko00030), and other metabolic pathways, thereby changing the precursor substances. The availability of SO<sub>2</sub> indirectly affects the formation of higher alcohols. In addition, excessive SO<sub>2</sub> affected the growth of the strain, leading to the emergence of a lag phase. We screened the ten most likely genes and constructed recombinant strains to evaluate the impact of each gene on the formation of higher alcohols. The results showed that <italic>ADH4, SER33</italic>, and <italic>GDH2</italic> are important genes of alcohol metabolism in <italic>S. cerevisiae</italic>. The isoamyl alcohol content of the EC1118a<italic>-ADH4</italic> strain decreased by 21.003%; The isobutanol content of the EC1118a<italic>-SER33</italic> strain was reduced by 71.346%; and the 2-phenylethanol content of EC1118a<italic>-GDH2</italic> strain was reduced by 25.198%.</p></sec><sec id="sec4"><title>Conclusion</title><p>This study lays a theoretical foundation for investigating the mechanism of initial addition of SO<sub>2</sub> in the synthesis of higher alcohols in <italic>S. cerevisiae</italic>, uncovering DEGs and key metabolic pathways related to the synthesis of higher alcohols, and provides guidance for regulating these mechanisms.</p></sec>