Transcriptional changes associated with ethanol tolerance in Saccharomyces cerevisiae

Appl Microbiol Biotechnol. 2010 Sep;88(1):231-9. doi: 10.1007/s00253-010-2760-7. Epub 2010 Jul 27.

Abstract

Saccharomyces spp. are widely used for ethanol production; however, fermentation productivity is negatively affected by the impact of ethanol accumulation on yeast metabolic rate and viability. This study used microarray and statistical two-way ANOVA analysis to compare and evaluate gene expression profiles of two previously generated ethanol-tolerant mutants, CM1 and SM1, with their parent, Saccharomyces cerevisiae W303-1A, in the presence and absence of ethanol stress. Although sharing the same parentage, the mutants were created differently: SM1 by adaptive evolution involving long-term exposure to ethanol stress and CM1 using chemical mutagenesis followed by adaptive evolution-based screening. Compared to the parent, differences in the expression levels of genes associated with a number of gene ontology categories in the mutants suggest that their improved ethanol stress response is a consequence of increased mitochondrial and NADH oxidation activities, stimulating glycolysis and other energy-yielding pathways. This leads to increased activity of energy-demanding processes associated with the production of proteins and plasma membrane components, which are necessary for acclimation to ethanol stress. It is suggested that a key function of the ethanol stress response is restoration of the NAD(+)/NADH redox balance, which increases glyceraldehyde-3-phosphate dehydrogenase activity, and higher glycolytic flux in the ethanol-stressed cell. Both mutants achieved this by a constitutive increase in carbon flux in the glycerol pathway as a means of increasing NADH oxidation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbon / metabolism
  • Drug Tolerance*
  • Ethanol / toxicity*
  • Gene Expression Profiling*
  • Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating) / metabolism
  • Glycerol / metabolism
  • Glycolysis
  • NAD / metabolism
  • Oxidation-Reduction
  • Saccharomyces cerevisiae / drug effects*
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism

Substances

  • NAD
  • Ethanol
  • Carbon
  • Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating)
  • Glycerol