Genome-wide transcriptional regulation in Saccharomyces cerevisiae in response to carbon dioxide

Sugar metabolism by Saccharomyces cerevisiae produces ample amounts of CO2 under both aerobic and anaerobic conditions. High solubility of C02 in fermentation media, contributing to enjoyable sensory properties of sparkling wine and beers by S. cerevisiae, might affect yeast metabolism. To elucidate the overlooked effects of C02 on yeast metabolism, we examined glucose fermentation by S. cerevisiae under CO2 as compared to N2 and O2 limited conditions. While both CO2 and N2 conditions are considered anaerobic, less glycerol and acetate but more ethanol were produced under C02 condition. Transcriptomic analysis revealed that significantly decreased mRNA levels of GPP 1 coding for glycerol-3-phosphate phosphatase in glycerol synthesis explained the reduced glycerol production under C02 condition. Besides, transcriptional regulations in signal transduction, carbohydrate synthesis, heme synthe¬sis, membrane and cell wall metabolism, and respiration were detected in response to C02. Interestingly, signal transduction was uniquely regulated under C02 condition, where upregulated genes (STE3, MSB2, WSC3, STE12, and TEC 1) in the signal sensors and transcriptional factors suggested that MAPK signaling pathway plays a critical role in C02 sensing and C02-induced metabolisms in yeast. Our study identifies C02 as an external stimulus for modulating metabolic activities in yeast and a transcriptional effector for diverse applications.