Protein synthesis of Btn2 under pronounced translation repression during the process of alcoholic fermentation and wine-making in yeast

Acute high-concentration ethanol (>9% v/v) has adverse effects on Saccharomyces cerevisiae, including the remarkable repression of bulk mRNA translation. Therefore, increased mRNA levels do not necessarily lead to an increase in the corresponding protein levels in yeast cells under severe ethanol stress. We previously identified that synthesis of Btn2 protein was efficiently induced even under the pronounced translation repression caused by acute severe ethanol stress under laboratory conditions. However, it remains to be clarified whether the translational activity is also repressed and whether the synthesis of Btn2 protein is induced during the process of alcoholic fermentation, in which the ethanol concentration increases gradually to reach high levels. In this study, we revealed that the pronounced translation repression and the translation of BTN2 are induced by high ethanol concentrations that form gradually during alcoholic fermentation using a wine yeast strain EC1118. Furthermore, we confirmed the induced expression of non-native genes driven by the BTN2 promoter during the later stage of the wine-making process. Our findings provide new information on the translation activity in yeast cells during alcoholic fermentation and suggest the utility of the BTN2 promoter for sustaining the fermentation efficiency and quality modification of alcoholic beverages.