Internal Trehalose Protects Endocytosis from Inhibition by Ethanol in<i>Saccharomyces cerevisiae</i>

Lucero, Pilar; Peñalver, Élida; Moreno, Eulalia; Lagunas, Rosario

doi:10.1128/aem.66.10.4456-4461.2000

Cited by 70 publications

(47 citation statements)

References 60 publications

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“…We confirmed trehalose as an important player, since the YPS163 tps1D strain had the strongest defect of all the mutants tested, and overexpression of Tps1 conferred higher ethanol resistance. Intriguingly, trehalose can also protect endocytosis from the inhibitory effects of ethanol (Lucero et al 2000), in addition to its traditional role in protein and membrane stabilization (Singer and Lindquist 1998).…”

Section: Discussionmentioning

confidence: 99%

Exploiting Natural Variation inSaccharomyces cerevisiaeto Identify Genes for Increased Ethanol Resistance

et al. 2010

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Ethanol production from lignocellulosic biomass holds promise as an alternative fuel. However, industrial stresses, including ethanol stress, limit microbial fermentation and thus prevent cost competitiveness with fossil fuels. To identify novel engineering targets for increased ethanol tolerance, we took advantage of natural diversity in wild Saccharomyces cerevisiae strains. We previously showed that an S288c-derived lab strain cannot acquire higher ethanol tolerance after a mild ethanol pretreatment, which is distinct from other stresses. Here, we measured acquired ethanol tolerance in a large panel of wild strains and show that most strains can acquire higher tolerance after pretreatment. We exploited this major phenotypic difference to address the mechanism of acquired ethanol tolerance, by comparing the global gene expression response to 5% ethanol in S288c and two wild strains. Hundreds of genes showed variation in ethanol-dependent gene expression across strains. Computational analysis identified several transcription factor modules and known coregulated genes as differentially expressed, implicating genetic variation in the ethanol signaling pathway. We used this information to identify genes required for acquisition of ethanol tolerance in wild strains, including new genes and processes not previously linked to ethanol tolerance, and four genes that increase ethanol tolerance when overexpressed. Our approach shows that comparative genomics across natural isolates can quickly identify genes for industrial engineering while expanding our understanding of natural diversity.

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Section: Discussionmentioning

confidence: 99%

Exploiting Natural Variation inSaccharomyces cerevisiaeto Identify Genes for Increased Ethanol Resistance

et al. 2010

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“…Trehalose manages to reduce ion leakage caused by ethanol (25). It also protects the cell from endocytosis inhibition due to high ethanol levels (22), which contributes to more efficient nitrogen utilization, and this may explain sustained cell viability in nitrogen-poor musts. As we found no significant change in medium osmolality (there was a change from 1,500 to 2,000 mOsm kg Ϫ1 , calculated from the contributions of sugar, ethanol, and glycerol), in our experiments trehalose was not accumulated in response to higher osmotic pressure.…”

Section: Discussionmentioning

confidence: 99%

Biomass Content Governs Fermentation Rate in Nitrogen-Deficient Wine Musts

Varela

Pizarro

Agosín

2004

Appl Environ Microbiol

194

179

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Problematic fermentations are common in the wine industry. Assimilable nitrogen deficiency is the most prevalent cause of sluggish fermentations and can reduce fermentation rates significantly. A lack of nitrogen diminishes a yeast's metabolic activity, as well as the biomass yield, although it has not been clear which of these two interdependent factors is more significant in sluggish fermentations. Under winemaking conditions with different initial nitrogen concentrations, metabolic flux analysis was used to isolate the effects. We quantified yeast physiology and identified key metabolic fluxes. We also performed cell concentration experiments to establish how biomass yield affects the fermentation rate. Intracellular analysis showed that trehalose accumulation, which is highly correlated with ethanol production, could be responsible for sustaining cell viability in nitrogen-poor musts independent of the initial assimilable nitrogen content. Other than the higher initial maintenance costs in sluggish fermentations, the main difference between normal and sluggish fermentations was that the metabolic flux distributions in nitrogen-deficient cultures revealed that the specific sugar uptake rate was substantially lower. The results of cell concentration experiments, however, showed that in spite of lower sugar uptake, adding biomass from sluggish cultures not only reduced the time to finish a problematic fermentation but also was less likely to affect the quality of the resulting wine as it did not alter the chemistry of the must.Sluggish and stuck fermentations are common in the wine industry. Factors that affect the yeast growth rate and that lead to problematic fermentations include limited nutrient contents, ethanol toxicity, fatty acid toxicity, temperature extremes (5), the ratio of nitrogen sources to carbon sources in the medium (21), and the initial quantity and quality of the amino acids (29). Sluggish cultures may prolong the process time from days to weeks. In stuck fermentations, high levels of residual sugar are left following the arrest of fermentation. Several difficulties occur at the cellular level; these include diminished sugar transport capacity, the inability of yeasts to produce compatible solutes in response to high osmolality (20,28), and cell membrane integrity issues in the presence of high concentrations of ethanol (8). As such mechanisms may act simultaneously in cells and to various extents, it is difficult to isolate and reproduce the mechanisms in stuck and sluggish fermentations.Quantitatively, nitrogen is the second most abundant nutrient in wine fermentations. It is essential for yeast metabolism and growth. Consequently, a lack of nitrogen triggers sluggish fermentations (1,8,13). In previous studies workers found differences in nitrogen-related curves (e.g., curves of biomass versus assimilable nitrogen) which indicated that the fermentation rate and biomass yield functions are distinct (9, 10; W. Agenbach, Proc. S. Afr. Soc. Enol. Vitic., p. 66-88, 1977). In other studies the ...

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“…It is clear that variation in ethanol tolerance of budding yeasts can be explained in terms of many factors such as lipid composition of the plasma membrane ( Jimenez and Benitez 1987;Lloyd et al 1993;Sajbidor et al 1995;Chi and Arneborg 2000;You et al 2003;Takagi et al 2005), accumulation of trehalose (Mansure et al 1994;Sharma 1997;Lucero et al 2000) or heat-shock protein Hsp104 (Sanchez et al 1992;Piper 1995), activity of plasma membrane H 1 -ATPase (Rosa and Sacorreia 1991;Supply et al 1995;Aguilera et al 2006), and mitochondrial stability (Aguilera and Benitez 1985;Ibeas and Jimenez 1997).…”

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confidence: 99%

Genetic Dissection of Ethanol Tolerance in the Budding Yeast Saccharomyces cerevisiae

et al. 2007

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Uncovering genetic control of variation in ethanol tolerance in natural populations of yeast Saccharomyces cerevisiae is essential for understanding the evolution of fermentation, the dominant lifestyle of the species, and for improving efficiency of selection for strains with high ethanol tolerance, a character of great economic value for the brewing and biofuel industries. To date, as many as 251 genes have been predicted to be involved in influencing this character. Candidacy of these genes was determined from a tested phenotypic effect following gene knockout, from an induced change in gene function under an ethanol stress condition, or by mutagenesis. This article represents the first genomics approach for dissecting genetic variation in ethanol tolerance between two yeast strains with a highly divergent trait phenotype. We developed a simple but reliable experimental protocol for scoring the phenotype and a set of STR/SNP markers evenly covering the whole genome. We created a mapping population comprising 319 segregants from crossing the parental strains. On the basis of the data sets, we find that the tolerance trait has a high heritability and that additive genetic variance dominates genetic variation of the trait. Segregation at five QTL detected has explained $50% of phenotypic variation; in particular, the major QTL mapped on yeast chromosome 9 has accounted for a quarter of the phenotypic variation. We integrated the QTL analysis with the predicted candidacy of ethanol resistance genes and found that only a few of these candidates fall in the QTL regions.

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Internal Trehalose Protects Endocytosis from Inhibition by Ethanol inSaccharomyces cerevisiae

Cited by 70 publications

References 60 publications

Exploiting Natural Variation inSaccharomyces cerevisiaeto Identify Genes for Increased Ethanol Resistance

Exploiting Natural Variation inSaccharomyces cerevisiaeto Identify Genes for Increased Ethanol Resistance

Biomass Content Governs Fermentation Rate in Nitrogen-Deficient Wine Musts

Genetic Dissection of Ethanol Tolerance in the Budding Yeast Saccharomyces cerevisiae

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