A set of nutrient limitations trigger yeast cell death in a nitrogen-dependent manner during wine alcoholic fermentation

PLoS One. 2017 Sep 18;12(9):e0184838. doi: 10.1371/journal.pone.0184838. eCollection 2017.

Abstract

Yeast cell death can occur during wine alcoholic fermentation. It is generally considered to result from ethanol stress that impacts membrane integrity. This cell death mainly occurs when grape musts processing reduces lipid availability, resulting in weaker membrane resistance to ethanol. However the mechanisms underlying cell death in these conditions remain unclear. We examined cell death occurrence considering yeast cells ability to elicit an appropriate response to a given nutrient limitation and thus survive starvation. We show here that a set of micronutrients (oleic acid, ergosterol, pantothenic acid and nicotinic acid) in low, growth-restricting concentrations trigger cell death in alcoholic fermentation when nitrogen level is high. We provide evidence that nitrogen signaling is involved in cell death and that either 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 are unable to store glycogen. Unexpectedly, transcriptome analyses did not reveal any major changes in stress genes expression, suggesting that post-transcriptional events critical for stress response were not triggered by micronutrient starvation. Our data point to the fact that yeast cell death results from yeast inability to trigger an appropriate stress response under some conditions of nutrient limitations most likely not encountered by yeast in the wild. Our conclusions provide a novel frame for considering both cell death and the management of nutrients during alcoholic fermentation.

MeSH terms

  • Fermentation / physiology*
  • Gene Deletion
  • Glycogen / genetics
  • Glycogen / metabolism
  • Nitrogen / metabolism*
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / growth & development*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Signal Transduction / physiology*
  • Stress, Physiological / physiology*
  • TOR Serine-Threonine Kinases / genetics
  • TOR Serine-Threonine Kinases / metabolism
  • Transcriptome / physiology*
  • Wine*

Substances

  • Saccharomyces cerevisiae Proteins
  • Glycogen
  • Protein Serine-Threonine Kinases
  • SCH9 protein, S cerevisiae
  • TOR Serine-Threonine Kinases
  • Nitrogen

Grants and funding

Lallemand SAS decided to publish the manuscript. Association Nationale de la Recherche et de la Technologie: Convention Industrielle de Formation par la Recherche n°2014/0017: had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.