Oxidative Stress Tolerance, Adenylate Cyclase, and Autophagy Are Key Players in the Chronological Life Span of Saccharomyces cerevisiae during Winemaking

Abstract

bMost grape juice fermentation takes place when yeast cells are in a nondividing state called the stationary phase. Under such circumstances, we aimed to identify the genetic determinants controlling longevity, known as the chronological life span. We identified commercial strains with both short (EC1118) and long (CSM) life spans in laboratory growth medium and compared them under diverse conditions. Strain CSM shows better tolerance to stresses, including oxidative stress, in the stationary phase. This is reflected during winemaking, when this strain has an increased maximum life span. Compared to EC1118, CSM overexpresses a mitochondrial rhodanese gene-like gene, RDL2, whose deletion leads to increased reactive oxygen species production at the end of fermentation and a correlative loss of viability at this point. EC1118 shows faster growth and higher expression of glycolytic genes, and this is related to greater PKA activity due to the upregulation of the adenylate cyclase gene. This phenotype has been linked to the presence of a ␦ element in its promoter, whose removal increases the life span. Finally, EC1118 exhibits a higher level of protein degradation by autophagy, which might help achieve fast growth at the expense of cellular structures and may be relevant for long-term survival under winemaking conditions.

Enhancement of Ethanol Fermentation in Saccharomyces cerevisiae Sake Yeast by Disrupting Mitophagy Function

“…Consistent with this hypothesis, the average cell area of the atg32⌬ mutant was 916 Ϯ 20.4 arbitrary units of Image J software (n ϭ 100), which was significantly smaller than that of its parent sake (17)(18)(19)44), to our knowledge, no study has defined the role of mitophagy in alcoholic fermentation. The present study demonstrates that mitophagy occurs during alcoholic fermentation and its disruption enhances fermentation.…”

Saccharomyces cerevisiae KNU5377 Stress Response during High-Temperature Ethanol Fermentation

“…The high toxicity of endogenously produced ethanol reduces cell viability, growth rate, and fermentation rate. Many mechanisms have been developed to help organisms withstand and/or prevent ethanol-induced damage during fermentation, including crossstress protection; yeast hybrids based on enological characterization (Belloch et al, 2008); membrane remodeling via changes in membrane (palmitoleic acid, oleic acid, and ergosterol) and cell wall composition (fatty acid, lipid, and isoprenoid metabolism); accumulation of amino acids (proline and tryptophan) and storage solutes (trehalose and glycogen) (Zhao and Bai, 2009); expression of molecular chaperones; transcriptional activation of V-ATPase and peroxisomal functions; enhancement of NADPH regeneration and redox balance (Cebollero et al, 2007;Ding et al, 2009;Orozco et al, 2012); genetic improvement through sexual cycle, parasexual hybridization and genetic engineering; and transcriptome remodeling of transcription factors, stress-related genes, and genes involved in signal transduction (Gibson et al, 2007;Ma and Liu, 2010a;Stanley et al, 2010). However, this approach has the intrinsic limitation that yeast adapts to different metabolic environments such as a high concentration of ethanol during fermentation.…”

A molecular genetic toolbox for Yarrowia lipolytica

“…10), has the potential to be used as a relative marker of oxidative stress. Consistent with Rdl2 expression levels correlating with stress tolerance in S. cerevisiae [84], monitored expression of Rdl2 under controlled and experimental growth conditions will aid optimization of bioproduct production in this obligate aerobe.

Fig. 10Mitochondrial and peroxisomal proteins under hydrogen peroxide stress.

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“…Rdl2p is a rhodanese-like protein which has thiosulfate sulfurtransferase activity [83]. Rdl2p function in S. cerevisiae is linked to H 2 O 2 detoxification, which contributes to life span in longer-lived wine fermentation yeast strains, where this protein is highly expressed in the late stages of fermentation [84]. Aim17p is implicated in mitochondrial biogenesis in S. cerevisiae [85, 86].…”