Polymorphism of the cell wall protein ccw7 encoding gene HSP150 in film-forming and sedimenting wine yeast strains.
Mónika Kovács (1), Igor Stuparevi č (2), Vladimir Mrsa (2), Anna Maráz (1)
(1) Department of Microbiology and Biotechnology, Faculty of Food Science, Corvinus University of Budapest, Hungary; (2) Department of Biochemistry, Faculty of Food Technology and Biotechnology, University of Zagreb, Croatia
Film-forming yeasts are able to form a pellicle on the surface of certain special dry wines. Our aim was to determine the possible role of cell wall proteins in film-formation. We looked for differences in the cell wall proteins of laboratory and film-forming S. cerevisiae yeast strains and found that all the film-forming strains had a smaller ccw7 protein than the reference strain. Therefore we designed a primer pair for PCR amplification of the protein-encoding gene HSP150, which could amplify an 1107 bp long sequence. We performed a PCR reaction using S. cerevisiae type strain, S288c strain, 26 film-forming and 17 sedimenting wine yeast strains. All the film-forming isolates had the PCR amplicon of the same size, but two of them contained additional amplicons. The sedimenting wine yeast strains showed extended length polymorphism of the amplicons. Sequence polymorphism of the gene was determined by RFLP analysis using RsaI, HaeIII and KpnI restriction enzymes. The film-forming yeast isolates showed identical patterns, except the isolates that had two amplicons. In the case of the latter strains we tried to determine whether the alleles of the HSP150 gene were segregating during meiosis and whether there was any connection between the film forming ability and the alleles. We found that the alleles of HSP150 gene segregated during meiosis, however both types of segregants maintained the film-forming ability.