Response to acetaldehyde stress in the yeast Saccharomyces cerevisiae involves a strain‐dependent regulation of several ALD genes and is mediatedby the general stress response pathway

Abstract

One of the stress conditions that yeast may encounter is the presence of acetaldehyde. In a previous study we identified that, in response to this stress, several HSP genes are induced that are also involved in the response to other forms of stress. Aldehyde dehydrogenases (ALDH) play an important role in yeast acetaldehyde metabolism (e.g. when cells are growing in ethanol). In this work we analyse the expression of the genes encoding these enzymes (ALD) and also the corresponding enzymatic activities under several growth conditions. We investigate three kinds of yeast strains: laboratory strains, strains involved in the alcoholic fermentation stage of wine production and flor yeasts (responsible for the biological ageing of sherry wines). The latter are very important to consider because they grow in media containing high ethanol concentrations, and produce important amounts of acetaldehyde. Under several growth conditions, further addition of acetaldehyde or ethanol in flor yeasts induced the expression of some ALD genes and led to an increase in ALDH activity. This result is consistent with their need to obtain energy from ethanol during biological ageing processes. Our data also suggest that post-transcriptional and/or post-translational mechanisms are involved in regulating the activity of these enzymes. Finally, analyses indicate that the Msn2/4p and Hsf1p transcription factors are necessary for HSP26, ALD2/3 and ALD4 gene expression under acetaldehyde stress, while PKA represses the expression of these genes.

Redox Interactions betweenSaccharomyces cerevisiaeandSaccharomyces uvarumin Mixed Culture under Enological Conditions

“…An early study showed that exogenously added acetaldehyde at a concentration of 1,000 mg/liter reduced the fermentation rate of glucose by S. cerevisiae by 30% (17). From a more fundamental point of view, such an addition of acetaldehyde initiates a transcriptional response in yeast cells that changes the expression of HSP genes (1), the genes encoding aldehyde dehydrogenases (ALD genes [2]) in order to allow the cells to use ethanol and acetaldehyde as carbon and energy sources under several circumstances.…”

Exposure ofSaccharomyces cerevisiaeto Acetaldehyde Induces Sulfur Amino Acid Metabolism and Polyamine Transporter Genes, Which Depend on Met4p and Haa1p Transcription Factors, Respectively

“…A few years ago several proteins were detected at a higher concentration in acetaldehyde-treated cells than in ethanol-treated cells, and it was thought likely that one of those proteins was Hsp90p (30). Recent studies carried out in our laboratory have demonstrated that the addition of acetaldehyde to exponentially growing cells provokes an induction in the transcription of stress response genes, such as HSP genes (3), and of aldehyde dehydrogenase (ALD) genes (4). The induction of all of these genes by acetaldehyde is positively regulated by Msn2/4p and Hsf1p proteins, while their expression is repressed by protein kinase A (4).…”

The Production of Secondary Metabolites with Flavour Potential during Brewing and Distilling Wort Fermentations

“…Acetaldehyde, ethanol and acetate metabolism in S. cerevisiae is complex [79] because several enzymes are involved with a dependence on the cell's redox balance. The two enzymes ultimately responsible for their metabolic pathways are alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), each of which consists of several isoenzymes.…”

“…The presence of acetaldehyde is one of the many stress conditions that yeast cells may encounter [79,82]. Several heat-shock proteins (HSP) genes are induced that are also involved in the response to other forms of stress (for example, ethanol) [83].…”