Impact of nutrient imbalance on wine alcoholic fermentations: nitrogen excess enhances yeast cell death in lipid-limited must

PLoS One. 2013 Apr 26;8(4):e61645. doi: 10.1371/journal.pone.0061645. Print 2013.

Abstract

We evaluated the consequences of nutritional imbalances, particularly lipid/nitrogen imbalances, on wine yeast survival during alcoholic fermentation. We report that lipid limitation (ergosterol limitation in our model) led to a rapid loss of viability during the stationary phase of fermentation and that the cell death rate is strongly modulated by nitrogen availability and nature. Yeast survival was reduced in the presence of excess nitrogen in lipid-limited fermentations. The rapidly dying yeast cells in fermentations in high nitrogen and lipid-limited conditions displayed a lower storage of the carbohydrates trehalose and glycogen than observed in nitrogen-limited cells. We studied the cell stress response using HSP12 promoter-driven GFP expression as a marker, and found that lipid limitation triggered a weaker stress response than nitrogen limitation. We used a SCH9-deleted strain to assess the involvement of nitrogen signalling pathways in the triggering of cell death. Deletion of SCH9 increased yeast viability in the presence of excess nitrogen, indicating that a signalling pathway acting through Sch9p is involved in this nitrogen-triggered cell death. We also show that various nitrogen sources, but not histidine or proline, provoked cell death. Our various findings indicate that lipid limitation does not elicit a transcriptional programme that leads to a stress response protecting yeast cells and that nitrogen excess triggers cell death by modulating this stress response, but not through HSP12. These results reveal a possibly negative role of nitrogen in fermentation, with reported effects referring to ergosterol limitation conditions. These effects should be taken into account in the management of alcoholic fermentations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Death / genetics
  • Ergosterol / metabolism*
  • Ethanol / metabolism
  • Fermentation
  • Gene Expression Regulation, Fungal*
  • Genes, Reporter
  • Glycogen / metabolism
  • Green Fluorescent Proteins
  • Heat-Shock Proteins / genetics
  • Heat-Shock Proteins / metabolism
  • Nitrogen / metabolism*
  • Promoter Regions, Genetic
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Signal Transduction
  • Trehalose / metabolism
  • Wine / microbiology*

Substances

  • HSP12 protein, S cerevisiae
  • Heat-Shock Proteins
  • Saccharomyces cerevisiae Proteins
  • Green Fluorescent Proteins
  • Ethanol
  • Glycogen
  • Trehalose
  • Protein Serine-Threonine Kinases
  • SCH9 protein, S cerevisiae
  • Nitrogen
  • Ergosterol

Grants and funding

Grants have been obtained from INRA. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.