Phenotypic switching of Saccharomyces cerevisiae wild strain.
Jaroslav Lev (1), Liba Vachova (2), Zdena Palkova (1)
(1) Dep. of Genetics, Microbiology, Faculty of Sciences, Vinicna 5, Praha, 128 43, Czech Republic; (2) Institute of Microbiology, Academy of Sciences, Videnska 1083, Praha 4, Czech Republic
We study morphology and development of colonies formed by Saccharomyces cerevisiae strains freshly isolated from natural environment. Contrary to majority of S. cerevisiae laboratory strains, wild strain BR-F creates fluffy colonies, in which cells are connected by abundant extracellular matrix containing large, not yet identified, glycoprotein. In laboratory, wild strain changes the behaviour and starts to form smooth colonies resembling those of laboratory strains. This domestication is accompanied by stop of the production of the matrix and by gene expression changes (Mol Microbiol 47: 745-54, 2003). In this study, we compared physiological properties and changes in morphology of wild fluffy and domesticated smooth colonies growing under conditions of different nutrient sources. In parallel, we estimated effect of nutrients on the frequency of domestication, i.e. on the frequency of cells undergoing the fluffy to smooth switch. The data regarding presence of extracellular matrix material and gene expression differences under respective conditions will be discussed. This work is supported by grants 204/03/H066, 204/02/0650 and 267/2004.