Résumé
Yeast cell death can occur during wine alcoholic fermentation. It is generally considered toresult from ethanol stress that impacts membrane integrity. This cell death mainly occurswhen grape musts processing reduces lipid availability, resulting in weaker membrane resistanceto ethanol. However the mechanisms underlying cell death in these conditions remainunclear. We examined cell death occurrence considering yeast cells ability to elicit an appropriateresponse to a given nutrient limitation and thus survive starvation. We show here thata set of micronutrients (oleic acid, ergosterol, pantothenic acid and nicotinic acid) in low,growth-restricting concentrations trigger cell death in alcoholic fermentation when nitrogenlevel is high. We provide evidence that nitrogen signaling is involved in cell death and thateither SCH9 deletion or Tor inhibition prevent cell death in several types of micronutrient limitation.Under such limitations, yeast cells fail to acquire any stress resistance and areunable to store glycogen. Unexpectedly, transcriptome analyses did not reveal any majorchanges in stress genes expression, suggesting that post-transcriptional events critical forstress response were not triggered by micronutrient starvation. Our data point to the factthat yeast cell death results from yeast inability to trigger an appropriate stress responseunder some conditions of nutrient limitations most likely not encountered by yeast in thewild. Our conclusions provide a novel frame for considering both cell death and the managementof nutrients during alcoholic fermentation.