Comparative analysis of genomes of cultured Saccharomyces yeasts.
Elena S. Naumova (1), Yulia V. Ivannikova (1), Nikolai N. Martynenko (2), Gennadi I. Naumov (1)
(1) Lab. of yeast genetics, GosNIIgenetika, I-Dorozhnyi,1, Moscow, 117545, Russia; (2) Moscow State University of Food Production, Moscow 125080, Russia
The genus Saccharomyces currently contains the species S. cerevisiae, S. bayanus, S. cariocanus, S. kudriavzevii, S. mikatae, S. paradoxus and a hybrid taxon S. pastorianus (syn. S. carlsbergensis ) (Naumov et al., 2000; Kurtzman, 2003). The six biological species can be crossed in any combination, however the resulting hybrids remain sterile having non-viable ascospores (Naumov, 1987, 1996; Naumov et al., 2000). We have conducted a comparative molecular-genetic study of cultured Saccharomyces yeasts, isolated from various fermentation processes. RFLP analysis of different genes, molecular karyotyping and Southern hybridization were used for differentiating Saccharomyces species and revealing hybrid strains. Hybrid composition of strains studied was established by genetic hybridization, flow cytometry and sequence analysis. In addition to brewer's yeasts, natural interspecific Saccharomyces hybrids are documented among bakers, wine strains and yeasts isolated from surface of red berries. According to genetic and molecular analyses, the hybrids have different genetic constitution, combining genomes of two or three Saccharomyces species. Role of auto- and allopolyploidization in genome evolution of Saccharomyces yeasts is discussed. This work was supported in part by grant from the Russian Fund for Basic Research (03-04-49245).