Comparative analysis of transcriptional responses to saline stress in the laboratory and brewing strains of Saccharomyces cerevisiae with DNA microarray

Abstract

To construct yeast strains showing tolerance to high salt concentration stress, we analyzed the transcriptional response to high NaCl concentration stress in the yeast Saccharomyces cerevisiae using DNA microarray and compared between two yeast strains, a laboratory strain and a brewing one, which is known as a stress-tolerant strain. Gene expression dynamically changed following the addition of NaCl in both yeast strains, but the degree of change in the gene expression level in the laboratory strain was larger than that in the brewing strain. The response of gene expression to the low NaCl concentration stress was faster than that to the high NaCl concentration stress in both strains. Expressions of the genes encoding enzymes involved in carbohydrate metabolism and energy production in both strains or amino acid metabolism in the brewing strain were increased under high NaCl concentration conditions. Moreover, the genes encoding sodium ion efflux pump and copper metallothionein proteins were more highly expressed in the brewing strain than in the laboratory strain. According to the results of transcriptome analysis, candidate genes for the creation of stress-tolerant strain were selected, and the effect of overexpression of candidate genes on the tolerance to high NaCl concentration stress was evaluated. Overexpression of the GPD1 gene encoding glycerol-3-phosphate dehydrogenase, ENA1 encoding sodium ion efflux protein, and CUP1 encoding copper metallothionein conferred high salt stress tolerance to yeast cells, and our selection of candidate genes for the creation of stress-tolerant yeast strains based on the transcriptome data was validated.

Enzymatic hydrolysis of food waste and ethanol fermentation

“…Trainotti and Stambuk [11] also reported that while salt stress dramatically affected specific growth rate and cell mass of S. cerevisiae, ethanol yield was not significantly reduced in the yeast extract peptone media containing 2% w/v glucose at 0.7 or 1.4 M NaCl. Hirasawa et al [18] observed that when S. cerevisiae was exposed to different concentrations of NaCl during its exponential growth, the specific growth rate radically decreased with the increasing salt content. These facts imply that although the presence of NaCl does not drastically affect ethanol yield, it inhibits the cell growth and substrate uptake so that eventually it extends the period of ethanol fermentation.…”

Yeast translational response to high salinity: Global analysis reveals regulation at multiple levels

“…Of these, 58 genes (z47%) are of an unknown biological process according to the Saccharomyces Genome Database (SGD). Only nine genes (YGR243W, GPD1, BTN2, HSP42, YDL023C, HSP12, CUP1-2, SPI1, and STL1) showed a relative increase of more than twofold in their steady-state mRNA levels, and all were previously reported to be induced in response to high salinity (Posas et al 2000;Yale and Bohnert 2001;Hirasawa et al 2006). The fact that only a few genes showed more than a twofold increase in mRNA levels is in agreement with reports describing a much reduced transcriptional changes in response to severe osmotic stress compared to mild stress conditions ( Fig.…”

“…Large-scale analyses of changes in steady-state mRNA levels following high salinity stress have demonstrated that the transcriptome response to this environmental stress is highly dynamic and varies greatly with time, salt type and concentration, and yeast strain used (Garcia et al 1997;Posas et al 2000;Yale and Bohnert 2001;O'Rourke and Herskowitz 2004;Hirasawa et al 2006;Gat-Viks and Shamir 2007). To establish the salt response of our strain (BY4741), we isolated RNA samples from cells at time zero or after 1 h of stress and used them for microarray analysis.…”

Resistance of Saccharomyces cerevisiae to High Concentrations of Furfural Is Based on NADPH-Dependent Reduction by at Least Two Oxireductases

“…Pivotal for this study is the use of chemostat cultures that allows us to study the furfural impact on steady-state growth, specifically avoiding the otherwise inevitable indirect effects of reduced or stopped growth (1,9,13,19,27). We reveal physiological and molecular features crucial for resistance and identify several genes involved in resistance.…”