Cooperative Roles of Trehalose and Heat Shock Proteins in the Response of Saccharomyces cerevisiae to Ethanol Stress

During the fermentation process, the growth and metabolism of Saccharomyces cerevisiae cells are often inhibited by the accumulated ethanol. The accumulation of trehalose, heat shock proteins (HSPs) and other protectants can respectively improve the ethanol tolerance of S. cerevisiae. In this study, the transcriptional level changes of genes involved in metabolisms of trehalose and HSPs in S. cerevisiae cells cultured at various concentrations of ethanol (i.e., 0, 5, 10, and 15% vol/vol) were determined by quantitative real-time polymerase chain reaction. The S. cerevisiae cells in ethanol-treated groups had higher expressions of genes which are responsible for encoding enzymes that are involved in the synthesis of trehalose (i.e., TPS1, TPS2, TPS3, and TSL1) and the HSPs synthetic genes than cells in control group. Moreover, a positive correlation was observed between the genes involved in the synthesis of trehalose and HSPs. On the contrary, except for NTH1, the expressions of genes involved in the degradation of trehalose decreased under ethanol stress. Given the similar expression patterns of genes involved in synthesis of trehalose and HSPs induced by ethanol and respective protective effects on cells against ethanol stress, trehalose might cooperate with HSPs to confer ethanol tolerance to S. cerevisiae.