Poster: Evolution

Abs # 784: Adaptations to oxidative stress in Saccharomyces cerevisiae

Presenter:	Miyazkai, Saori , saori@life.uiuc.edu
Authors	Miyazkai, Saori  (A)   Weinberg, Dahlia  (A)   Idleman, Ursulla  (A)   Nevo, Eviatar  (B)   Bohnert, Hans J.  (A)
Affiliations:	(A): Department of Plant Biology and Department of Crop Sciences, University of Illinois (B): Institute of Evolution, University of Haifa

We are interested in determining the capacity of yeast strains found in close spatial proximity, but presumably isolated climatic niches, to adapt to severe abiotic stress by monitoring gene expression responses of different isolates. Strains of Saccharomyces cerevisiae were collected and isolated from different locations along a microclimatic gradient at “Evolution Canyon”, Israel (Nevo E. [1997] Theoret Popul Biol 52: 231-243). Seventeen strains characterized by dry conditions and high irradiation were selected from the south-facing slope (SFS), 19 from the north-facing slope (NFS), characterized by moist and low irradiation conditions, and 6 strains from the valley bottom. Survival rates for three different stresses (NaCl, H2O2, and mannitol) were tested, and the rates of recovery were compared. Sensitive strains for H2O2 included a lab strain S150-2B and strains from the NFS. Salinity tolerance segregated with peroxide tolerance. Microarray analysis using a yeast genome array (6034 genes) and hierarchical clustering of regulated transcripts indicated maximum linkage of expression profiles between strains that showed the same type of stress response. Genes commonly up-regulated in tolerant strains in response to H2O2 and not-up-regulated in sensitive strains were related in cell wall biosynthesis, fatty acid metabolism, pentose phosphate cycle, and methionine biosynthesis. In contrast, genes preferentially induced in sensitive strains identified oxidative stress-related genes (e.g., glutaredoxin and flavo-hemoglobin) and genes for functions in oxidative phosphorylation. In all strains, the number of regulated, functionally unknown genes amounted to a substantial number (NSF DBI-0223905 and Ancell-Teicher Foundation for Molecular Genetics & Evolution to E. Nevo).