Genome comparison and evolutionary analysis of different industrial lager yeasts (Saccharomyces pastorianus)

Fermented beverages, especially beer, have accompanied human civilizations throughout our history. The yeast strains used for lager beer fermentation have long been recognized as hybrids between two Saccharomyces species. For hundreds of years, lager yeast (Saccharomyces pastorianus) has been subjected to multiple rounds of domestication owing to artificial selection during beer production. As a result, this species comprises a genetically diverse collection of strains that are used in different breweries. However, the scope of genetic diversity captured during the domesticated evolution of this species remains to be determined. To begin to address this, we collected the genome information of the only four lager strains that had been whole-genome sequenced. For the first time, genome comparison was conducted between lager yeasts and clear signatures were found that defined each industrial yeast strain. The genetic variation comprises both single nucleotide polymorphisms and insertions and deletions. In addition, the core-pan genome was introduced for the first time to the genomic analysis of lager yeasts, detecting numerous strain-specific and species-shared genes. Furthermore, phylogenetic tree and synteny analysis results obtained in this study revealed information regarding the evolutionary relationship and group differentiation of studied strains. Genome comparison of the lager strains will, therefore, enable the characterization of the overall genetic diversity of this species, assist in the identification of genomic loci that play important roles in regulating key industrial phenotypes, and highlight the understanding of the hybrid nature and evolutionary details. Copyright (C) 2016 The Institute of Brewing & Distilling