title: Novel wine yeast with mutations in YAP1 that produce less acetic acid during fermentation.
abstract: Acetic acid, a byproduct formed during yeast alcoholic fermentation, is the main component of volatile acidity (VA). When present in high concentrations in wine, acetic acid imparts an undesirable 'vinegary' character that results in a significant reduction in quality and sales. Previously, it has been shown that saké yeast strains resistant to the antifungal cerulenin produce significantly lower levels of VA. In this study, we used a classical mutagenesis method to isolate a series of cerulenin-resistant strains, derived from a commercial diploid wine yeast. Four of the selected strains showed a consistent low-VA production phenotype after small-scale fermentation of different white and red grape musts. Specific mutations in YAP1, a gene encoding a transcription factor required for oxidative stress tolerance, were found in three of the four low-VA strains. When integrated into the genome of a haploid wine strain, the mutated YAP1 alleles partially reproduced the low-VA production phenotype of the diploid cerulenin-resistant strains, suggesting that YAP1 might play a role in (regulating) acetic acid production during fermentation. This study offers prospects for the development of low-VA wine yeast starter strains that could assist winemakers in their effort to consistently produce wine to definable quality specifications.
authors.affiliation: The Australian Wine Research Institute, Glen Osmond, SA, Australia.
authors.forename: Antonio G
authors.initials: AG
authors.lastname: Cordente
authors.forename: Gustavo
authors.initials: G
authors.lastname: Cordero-Bueso
authors.forename: Isak S
authors.initials: IS
authors.lastname: Pretorius
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Curtin
mesh_terms: D019342:Acetic Acid / Q000378:metabolism*; D000426:Alcohol Dehydrogenase / Q000378:metabolism; D000445:Aldehyde Oxidoreductases / Q000378:metabolism; D000935:Antifungal Agents / Q000494:pharmacology*; D001483:Base Sequence; D002569:Cerulenin / Q000494:pharmacology*; D025141:Drug Resistance, Fungal; D004952:Esters / Q000378:metabolism; D005020:Ethyl Methanesulfonate / Q000494:pharmacology; D005285:Fermentation; D008969:Molecular Sequence Data; D016296:Mutagenesis; D018384:Oxidative Stress; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000201:enzymology / Q000235:genetics* / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D027843:Vitis / Q000382:microbiology; D014920:Wine / Q000382:microbiology / Q000592:standards*
chemical_list: D000935:Antifungal Agents; D004952:Esters; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C086677:YAP1 protein, S cerevisiae; D002569:Cerulenin; D005020:Ethyl Methanesulfonate; D000426:Alcohol Dehydrogenase; D000445:Aldehyde Oxidoreductases; C018699:aldehyde dehydrogenase (NAD(P)+); D019342:Acetic Acid