基于代谢组学和转录组学分析工业面包酵母(Saccharomyces cerevisiae)ABY3冷冻胁迫应答机制

Metabolomic and Transcriptomic Analysis of Response Mechanism of Baker’s Yeast to Freezing Stress

为研究面包酵母(Saccharomyces cerevisiae)响应冷冻胁迫的机理,对面包酵母-20℃处理7 d前后的发酵菌液进行胞内的代谢组学和转录组学分析。在-20℃、7 d的环境胁迫下,面包酵母不加糖模拟面团发酵后的存活率为43%,发酵力下降42%。冷冻胁迫下,面包酵母胞内24种代谢物的变化与494种基因的表达差异与应答机制相关。通过差异代谢通路分析得出:冷冻胁迫下,胞内氨基酸的匮乏与质膜僵硬化可能是影响细胞生长和发酵性能的主要原因,而胞内不饱和脂肪酸相对含量的增加和海藻糖的积累并不能消除低温对细胞的损伤。研究结果可完善酵母冷冻胁迫应答机理,为耐性调节机制的研究提供思路,对冷冻面团的优化和技术发展具有重要意义。

In order to study the mechanism underlying the response of baker’s yeast(Saccharomyces cerevisiae)to freezing stress,intracellular metabolomic and transcriptomic analysis was carried out on the fermentation broth of baker’s yeast before and after treatment at−20℃for 7 days.In this experiment,the survival rate of baker’s yeast undergoing environmental stress was 43%after simulated dough fermentation without added sugar,and the fermentation capability was decreased by 42%as compared to the untreated control.The changes of 24 intracellular metabolites and the differential expression of 494 genes in S.cerevisiae were related to the response to freezing stress.Through the analysis of differential metabolic pathways,we found that the lack of intracellular amino acids and plasma membrane stiffness may be the major factors affecting cell growth and fermentation performance under freezing stress.However,the increase in the relative content of intracellular unsaturated fatty acids and the accumulation of trehalose could not eliminate the cellular damage caused by low temperatures.These results can improve our understanding of the response mechanism of yeast to freezing stress,which will provide new ideas for future studies of the resistance regulatory mechanism in yeast,and will be of great significance for the optimization and technical development of frozen dough.