AUTHOR=Macías Laura G. , Morard Miguel , Toft Christina , Barrio Eladio 

TITLE=Comparative Genomics Between Saccharomyces kudriavzevii and S. cerevisiae Applied to Identify Mechanisms Involved in Adaptation

JOURNAL=Frontiers in Genetics

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2019.00187

DOI=10.3389/fgene.2019.00187

ISSN=1664-8021

ABSTRACT=<p>Yeasts belonging to the <italic>Saccharomyces</italic> genus play an important role in human-driven fermentations. The species <italic>S. cerevisiae</italic> has been widely studied because it is the dominant yeast in most fermentations and it has been widely used as a model eukaryotic organism. Recently, other species of the <italic>Saccharomyces</italic> genus are gaining interest to solve the new challenges that the fermentation industry are facing. One of these species is <italic>S. kudriavzevii,</italic> which exhibits interesting physiological properties compared to <italic>S. cerevisiae</italic>, such as a better adaptation to grow at low temperatures, a higher glycerol synthesis and lower ethanol production. The aim of this study is to understand the molecular basis behind these phenotypic differences of biotechnological interest by using a species-based comparative genomics approach. In this work, we sequenced, assembled and annotated two new genomes of <italic>S. kudriavzevii</italic>. We used a combination of different statistical methods to identify functional divergence, signatures of positive selection and acceleration of substitution rates at specific amino acid sites of proteins in <italic>S. kudriavzevii</italic> when compared to <italic>S. cerevisiae</italic>, and vice versa. We provide a list of candidate genes in which positive selection could be acting during the evolution of both <italic>S. cerevisiae</italic> and <italic>S. kudriavzevii</italic> clades. Some of them could be related to certain important differences in metabolism previously reported by other authors such us <italic>DAL3</italic> and <italic>ARO4</italic>, involved in nitrogen assimilation and amino acid biosynthesis. In addition, three of those genes (<italic>FBA1, ZIP1,</italic> and <italic>RQC2</italic>) showed accelerated evolutionary rates in <italic>Sk</italic> branch. Finally, genes of the riboflavin biosynthesis were also among those genes with a significant higher rate of nucleotide substitution and those proteins have amino acid positions contributing to functional divergence.</p>