Recombination, admixture and genome instability shape the genomic landscape of < i > Saccharomyces cerevisiae < /i > derived from spontaneous grape ferments

by Chris M. Ward, Cristobal A. Onetto, Steven Van Den Heuvel, Kathleen M. Cuijvers, Laura J. Hale, Anthony R. Borneman Cultural exchange of fermentation techniques has driven the spread ofSaccharomyces cerevisiae across the globe, establishing natural populations in many countries. Despite this, Oceania is thought to lack native populations ofS.cerevisiae, only being introduced after colonisation. Here we investigate the genomic landscape of 411S.cerevisiae isolated from spontaneous grape fermentations in Australia across multiple locations, years, and grape cultivars. Spontaneous fermentations contained highly recombined mosaic strains that exhibited high levels of genome instability. Assigning genomic windows to putative ancestral origin revealed that few closely related starter lineages have come to dominate the genetic landscape, contributing most of the genetic variation. Fine-scale phylogenetic analysis of loci not observed in strains of commercial wine origin identified widespread admixture with European derived beer yeast along with three independent admixture events from potentially endemic Oceanic lineages that was associated with genome instability. Finally, we investigated Australian ecological niches for basal isolates, identifying phylogenetically distinctS.cerevisiae of non-European, non-domesticated origin associated with admixture loci. Our results illustrate the effect commercial use of microbes may have on local microorganism genetic diversity and demonstr...
Source: PLoS Genetics - Category: Genetics & Stem Cells Authors: Source Type: research