外源海藻糖对啤酒酵母在热胁迫下的保护作用

Protective Effects of Exogenous Trehalose on Brewer’s Yeast under Heat Stress

摘要:

为探究外源海藻糖对啤酒酵母在热胁迫下的保护作用，作者在3个热胁迫条件下检测外源海藻糖对啤酒酵母活力及活性的影响，并通过分析转录组数据对热胁迫下外源海藻糖对啤酒酵母的保护作用机理进行初步分析。结果表明，外源海藻糖可以提升啤酒酵母的耐热性，但具有一定限度，温度的升高和胁迫时间的延长导致不同浓度海藻糖的作用差别减小。另外，添加海藻糖可以增加酵母胞内海藻糖质量分数，添加海藻糖对啤酒酵母转录水平上的影响主要体现在核糖体的合成和相关功能上。结合本研究推测，外源海藻糖对啤酒酵母在热胁迫下的保护作用是通过增加胞内海藻糖质量分数实现的，上升的胞内海藻糖质量分数促进了核糖体合成及相关代谢，使核糖体功能增强，进而实现对啤酒酵母耐热性的增强。

Abstract:

The protective effect of exogenous trehalose on brewer's yeast under heat stress was investigated via measuring the cell viability and vitality under 3 heat stress conditions, and the underlying mechanism was further studied via preliminary transcriptional analysis. As a result, exogenous trehalose was sufficient in improving the heat tolerance of brewer's yeast within the limited period and temperature ranges. The differences in the protective effects of various concentrations of trehaloseshrank with the increase of treatment temperature and duration. Moreover, the addition of exogenous trehalose elevated the intracellular trehalose level. Transcriptional analysis revealed that differentially expressed genes caused by trehaloseaddition mainly centered in ribosome biogenesis and related functions. It was thus speculated that the improved heat tolerance of brewer's yeast after adding exogenous trehalose to the culture medium was achieved by the elevated intracellular trehalose level. The increased level of intracellular trehalose promoted ribosome pathways andstrengthened the ribosome functions, further improving the heat tolerance of brewer's yeast.