Exogenous Trehalose Assists Zygosaccharomyces rouxii in Resisting High-Temperature Stress Mainly by Activating Genes Rather than Entering Metabolism

Zygosaccharomyces rouxii is a typical aroma-producing yeast in food brewing, but it has low heat resistance and poor proliferation ability at high temperature. Trehalose is generally considered to be a protective agent that helps stable yeast cells resist heat shock stress, but its functional mechanism for yeast cells in the adaptation period under heat stress is unclear. In this study, the physiological metabolism changes, specific gene transcription expression characteristics, and transcriptome differences of Z. rouxii under different carbon sources under high-temperature stress (40 °C) were compared to explore the mechanism of trehalose inducing Z. rouxii to recover and proliferate under high-temperature stress during the adaptation period. The results showed that high concentration of trehalose (20% Tre) could not be used as the main carbon source for the proliferation of Z. rouxii under long-term high-temperature stress, but it helped to maintain the stability of the cell population. The intracellular trehalose of Z. rouxii was mainly derived from the synthesis and metabolism of intracellular glucose, and the extracellular acetic acid concentration showed an upward trend with the improvement of yeast growth. A high concentration of trehalose (20% Tre) can promote the expression of high glucose receptor gene GRT2 (12.0-fold) and induce the up-regulation of HSF1 (27.1-fold), MSN4 (58.9-fold), HXK1 (8.3-fold), and other signal transduction protein genes, and the increase of trehalose concentration will maintain the temporal up-regulation of these genes. Transcriptome analysis showed that trehalose concentration and the presence of glucose had a significant effect on the gene expression of Z. rouxii under high-temperature stress. In summary, trehalose assists Z. rouxii in adapting to high temperature by changing gene expression levels, and assists Z. rouxii in absorbing glucose to achieve cell proliferation.