An inverse correlation between stress resistance and stuck fermentations in wine yeasts. A molecular study

During alcoholic fermentations yeast cells are subjected to several stress conditions and, therefore, yeasts have developed molecular mechanisms in or der to resist this adverse situation. The mechanisms involved in stress res ponse have been studied in Saccharomyces cerevisiae laboratory strains. How ever a better understanding of these mechanisms in wine yeasts could open t he possibility to improve the fermentation process. In this work an analysi s of the stress response in three wine yeasts has been carried out by study ing the expression of several representative genes under several stress con ditions which occur during fermentation. We propose a simplified method to study how these stress conditions affect the viability of yeast cells. Usin g this approach an inverse correlation between stress-resistance and stuck fermentations has been found. We also have preliminary data about the use o f the HSP12 gene as a molecular marker for stress-resistance in wine yeasts . (C) 1999 John Wiley & Sons, Inc.