Yeast is one of the microorganisms widely used in fermentation industry, and its high temperature resistance plays an important role in fermentation. However, the complex regulatory process of cell tolerance to heat stress has not been fully understood. Therefore, this study carried out basic research on high temperature resistant yeast at 28℃, 37℃ and 43℃, including morphological observation, determination of trehalose content and cell membrane permeability, and combined with RNA-seq technology to screen differentially expressed genes in yeast responding to high temperature stress at the transcriptome level. The results showed that under heat treatment conditions, the macroscopic and microscopic morphology of yeast cells were changed, the selective permeability of cell membrane was changed, and the intracellular trehalose was accumulated. Different nitrogen sources and inorganic salt ions can improve the high temperature tolerance of yeast ZG-3. In addition, a total of 517 differentially expressed genes were screened by comparing the temperature resistant yeast at 28℃ with that at 37℃, among which 435 genes were up-regulated and 82 genes were down-regulated. A total of 632 differentially expressed genes were screened at 37℃ compared with that at 43℃, among which 393 genes were up-regulated and 239 genes were down-regulated. Among them, SSA3, SSA4, HSP82, SSE1, KAR2, FES1, HSP26, HSP42 genes of the heat shock protein family were significantly up-regulated, which improved the basic and acquired heat tolerance of yeast. This study combined physical and chemical properties analysis and transcriptome analysis to preliminarily explore the differentially expressed genes in yeast in response to high temperature stress, which provides a theoretical basis for further study of yeast high temperature tolerance.

Background: As for thermotolerance of yeasts, early research focuses on comparative biology. However, there is rare research on genes related to thermotolerance of yeasts.Morphological observation, trehalose concentration, and cellular structure of a thermotolerant yeast strain were basically studied. Together with RNA-Seq, the differentially expressed genes (DGEs) related to the thermotolerance of the liquor-making yeast strain at 28, 37 and 43 ºC were screened out at the transcriptome level. It was found trehalose concentration increment can improve thermotolerance,and the destruction of strain cellular structure led to a decline in thermotolerance.Results: After treatment of the thermotolerant yeast strain at 28 ºC compared with 37 ºC, 517 DGEs were screened out, including 435 upregulated genes and 82 downregulated genes. After treatment at 37 ºC relative to 43 ºC, 632 DGEs were recognized, including 393 upregulated genes and 239 downregulated genes.Conclusions: By combining physicochemical property analysis and transcriptome analysis, this preliminary study uncovers the DEGs responsible for the thermotolerance of a thermotolerant yeast strain, and theoretically underlies further research on the high temperature tolerance of liquor-making yeasts.