Expression of stress response genes in wine strains with different fermentative behavior.

The response to adverse growth conditions in yeast depends on the activation of signal transduction pathways which result in transcriptional changes and synthesis of protective molecules. During wine production, yeast cells are affected by a plethora of stress situations. In this work we have analyzed the fermentative behavior in synthetic must for six different wine yeast strains. In addition, we followed the expression of several stress response genes during the first half of the vinification. Our results indicate that common patterns of stress response are found among all the strains, but also that a subset of genes are differentially expressed according to the fermentative behavior of the various strains. Particularly, in the strains with the most severe fermentative problems, higher (and in some cases maintained) mRNA levels of many genes were found. The relevance of an equilibrium between stress response and growth efficiency during wine fermentation is discussed.