The genome sequence of the wine yeast VIN7 reveals an allotriploid hybrid genome with Saccharomyces cerevisiae and Saccharomyces kudriavzevii origins

The vast majority of wine fermentations are performed principally by Saccharomyces cerevisiae. However, there are a growing number of instances in which other species of Saccharomyces play a predominant role. Interestingly, the presence of these other yeast species generally occurs via the formation of interspecific hybrids that contain genomic contributions from both S.cerevisiae and non-S.cerevisiae species. However, despite the large number of wine strains that are characterized at the genomic level, there remains limited information regarding the detailed genomic structure of hybrids used in winemaking. To address this, we describe the genome sequence of the thiol-releasing commercial wine yeast hybrid VIN7. VIN7 is shown to be an almost complete allotriploid interspecific hybrid that is comprised of a heterozygous diploid complement of S.cerevisiae chromosomes and a haploid Saccharomyces kudriavzevii genomic contribution. Both parental strains appear to be of European origin, with the S.cerevisiae parent being closely related to, but distinct from, the commercial wine yeasts QA23 and EC1118. In addition, several instances of chromosomal rearrangement between S.cerevisiae and S.kudriavzevii sequences were observed that may mark the early stages of hybrid genome consolidation.