MET2 affects production of hydrogen sulfide during wine fermentation

Abstract

The production of hydrogen sulfide (H2S) during yeast fermentation contributes negatively to wine aroma. We have mapped naturally occurring mutations in commercial wine strains that affect production of H2S. A dominant R310G mutant allele of MET2, which encodes homoserine O-acetyltransferase, is present in several wine yeast strains as well as in the main lab strain S288c. Reciprocal hemizygosity and allele swap experiments demonstrated that the MET2 R310G allele confers reduced H2S production. Mutations were also identified in genes encoding the two subunits of sulfite reductase, MET5 and MET10, which were associated with reduced H2S production. The most severe of these, an allele of MET10, showed five additional phenotypes: reduced growth rate on sulfate, elevated secretion of sulfite, and reduced production in wine of three volatile sulfur compounds: methionol, carbon disulfide and methylthioacetate. Alleles of MET5 and MET10, but not MET2, affected H2S production measured by colour assays on BiGGY indicator agar, but MET2 effects were seen when bismuth was added to agar plates made with Sauvignon blanc grape juice. Collectively, the data are consistent with the hypothesis that H2S production during wine fermentation results predominantly from enzyme activity in the sulfur assimilation pathway. Lower H2S production results from mutations that reduce the activity of sulfite reductase, the enzyme that produces H2S, or that increase the activity of L-homoserine-O-acetyltransferase, which produces substrate for the next step in the sulfur assimilation pathway.

Molecular and Phenotypic Characterization of Metschnikowia pulcherrima Strains from Douro Wine Region

“…Previously, Lage et al [22] have observed the same effect using a co-culture of H. guilliermondii and the same commercial strain of S. cerevisiae used herein. Later, Barbosa et al [79] showed that the presence of the non-Saccharomyces strain of H. guilliermondii had an evident regulatory control of S. cerevisiae genes that impact H 2 S liberation during wine fermentation [86][87][88]. In this line, we could only speculate that Mp39 could have a similar effect on the transcriptome of S. cerevisiae.…”

Transcriptional response of Saccharomyces cerevisiae to low temperature during wine fermentation

“…M2 was selected as the genetic background for the transcriptomic study and for the F 1 hybrids because it is homozygous at all of the ten microsatellite loci tested and a good fermenter at low temperatures. The microsatellite genotype of M2 is identical to AWRI796, Oenoferm Tipico, Lalvin W15, and Anchor WE372 (Gardner et al 2006) and the full genome sequence is available for M2 (Huang et al 2014), AWRI796 (Borneman et al 2011) and WE372 (Cromie et al 2013).…”

European derivedSaccharomyces cerevisiaecolonisation of New Zealand vineyards aided by humans

“…In addition to the 52 genomes sequenced here, a further 72 S. cerevisiae and 37 S. paradoxus genomes were obtained from the Saccharomyces Genome Database (http://yeastgenome.org), NCBI, the Saccharomyces Genome Resequencing Project (https://sanger.ac.uk/research/projects/genomeinformatics/sgrp.html) and from Huang, Roncoroni and Gardner (2014) in the form of consensus genomes and/or raw data. To obtain an accurate estimation of the relatedness of the genomes, we extracted the well-known set of 106 orthologous loci spread through the genome of S. cerevisiae and present in all Saccharomyces species (Rokas et al .…”