Ectopic Expression of Sweet Potato MuS1 Increases Acquired Stress Tolerance and Fermentation Yield in Saccharomyces cerevisiae

The MuS1 gene is highly homologous to many stress-related proteins in plants. Here, we characterized whether a new candidate gene, MuS1, is related to multiple stress tolerance in yeast as it is in plants. Transgenic yeast strain expressing MuS1 were more resistant to hydrogen peroxide, menadione, high salinity, metals (i.e., cadmium, copper, iron, and zinc), ethanol, and lactic acid than wild-type strain transformed with a vector alone. In addition, the alcohol yield of the transgenic yeast strain was higher than that of the wild-type strain during the batch fermentation process. These results show that MuS1-expressing transgenic yeast strain exhibits enhanced alcohol yield as well as tolerance to abiotic stresses, especially metal stress.