Detection of protein markers for autophagy, autolysis and apoptosis processes in aSaccharomyces cerevisiaewine flor yeast strain when forming biofilm

Abstract

AbstractYeast autophagy, autolysis and apoptosis are triggered by nutrient starvation conditions that usually take place in winemaking. Biological aging of Sherry wines constitutes an enological environment suitable for the induction of these biological processes due to the scarcity of nutrients and formation of yeast social communities, i.e. biofilm; however, few studies have been carried out in this regard. Here, we perform a proteomic analysis to detect any autolysis/autophagy/apoptosis protein markers and/or proteins potentially related to these processes under flor forming and fermentative conditions. The scarce presence of autophagy proteins in flor biofilm forming conditions, the existence of autophagy inhibitors (e.g. Pph21p), and high quantity of crucial proteins for autolysis and apoptosis, Pep4p and Mca1p, respectively; indicate that autophagy may be silenced while autolysis and apoptosis are activated when the yeasts are forming flor. This is the first time that autophagy, autolysis and apoptosis have been studied as a whole in flor yeast to our knowledge.ImportanceFlor yeasts areSaccharomyces cerevisiaestrains traditionally used in winemaking and have the ability to survive under starvation conditions and form biofilm. These capabilities make flor yeast interesting organisms to study the biological processes of autophagy, autolysis and apoptosis. With this work, we aim to seek for evidences—protein markers— of these processes in a flor yeast when subjected to biofilm forming and fermentative conditions. Our results suggest that while autophagy may be silenced under biofilm conditions, autolysis and apoptosis are activated. The data provided improve the knowledge of yeast behavior under different enological conditions and can further improve quality of wines in a near future.