Oxidative Stress Responses in Yeast Strains, Saccharomyces cerevisiae, from ?Evolution Canyon?, Israel

Abstract

The genome of baker’s yeast, Saccharomyces cerevisiae, has been sequenced, many genes have been deleted for phenotypic analysis, and the tools to study gene and protein interaction and the functions of the large number of functionally unknown genes have made yeast the most advanced model for the analysis of eukaryotic organisms. The yeast research community has provided a paradigm for work in the genomics era of biology of which Professor Ruis has been an early protagonist. The genomics view is now contributing to initiate research in molecular evolution. We have taken strains from “Evolution Canyon”, Israel, for an analysis by microarray hybridizations of the response of wild yeast accessions to environmental stress, in particular oxidative stress. Strains were selected from the “African” south-facing slope (SFS) of the canyon, characterized by xeric conditions and high irradiation, from the “European” north-facing slope (NFS), characterized by mesic conditions and low irradiation, and from the valley bottom. H2O2-sensitive strains included a laboratory strain (S150-2B) and most strains from the NFS. Statistically supported is a correlation between peroxide tolerance, the SFS, and micro-niche within a slope. Hierarchical clustering of regulated transcripts indicated maximum linkage of expression profiles between strains that showed the same phenotypic stress response. The analyses indicate strain-specific adaptive micro-niche evolution along the microclimatic gradient of “Evolution Canyon” that determine the response to oxidative stress.