Mating Pheromones of Saccharomyces kluyveri : Pheromone Interactions Between Saccharomyces kluyveri and Saccharomyces cerevisiae

Abstract

Saccharomyces kluyveri is a heterothallic yeast with two allelic mating types denoted as a-k and α- k by analogy with Saccharomyces cerevisiae and from the work described here. S. kluyveri produces mating pheromones analogous to those of S. cerevisiae , but which appear to have different specificity. S. kluyveri thus differs from S. cerevisiae, Hansenula wingei , and Schizosaccharomyces pombe in that it exhibits both strong constitutive agglutination and mating pheromones. α- k cells produce a pheromone (“α- k -factor”) which causes a-k cells to arrest in the G1 phase of the cell cycle and to undergo a morphological change. After a period of time dependent on the concentration of α- k -factor, cells exposed to the factor resume cell division. α- k -factor has no effect on a-k /α- k diploids or on α- k cells, but at high concentration does induce G1 arrest of S. cerevisiae a cells ( a -c). a-k cells produce a pheromone (“ a-k -factor”) which causes α- k cells to exhibit a morphological change. In addition, a-k cells exhibit the Bar phenotype with respect to α- k -factor. Partially purified preparations of S. cerevisiae α-factor are more active in inducing G1 arrest of a-k cells than of a -c cells. A more purified preparation of α-c-factor is less active against a-k cells than a -c cells, suggesting that an additional factor (KRE, kluyveri response enhancer) may be lost during purification. Attempts to mate S. kluyveri and S. cerevisiae cells by prototroph selection and by cell-to-cell mating have been unsuccessful with all combinations of mating types. Thus, S. cerevisiae and S. kluyveri are incompatible for mating even though their pheromones exhibit some physiological cross-reaction.

Existence of cerebroside in and its related species

“…kluyveri has been shown to be an outlying species of the genus Saccharomyces from its ecological, physiological, and genetic characteristics [23]. However, cells of S. kluyveri can be cultured as either stable haploids or diploids [24] and applied for classical genetic analysis, which has provided the essential background for the molecular biology of S. cerevisiae. S. cerevisiae-based plasmids have been replicated and maintained in auxotrophic mutants of S. kluyveri after transformation by the lithium method [25].…”

Phylogenetic relationships among species of Saccharomyces, Schizosaccharomyces, Debaryomyces and Schwanniomyces determined from partial ribosomal RNA sequences

“…Saccharomyces paradoxus may also be a partial amphidiploid, but, if so, this is not evident from the rRNA sequences which show similarities in region 25s-635 with both S. cerevisiae and S. hayanus. We had expected S. kluyveri to be part of the S. cerevisiae complex because of the weak apheromone response that it exhibits with S. cerevisiae (McCullough and Herskowitz, 1979). In view of the large genetic distance indicated by rRNA divergence, these two species are the least related pair of yeasts known to exhibit an interspecific pheromone response (Kurtzman and Phaff, 1987).…”

Sexual behavior and its pheromonal regulation in ascosporogenous yeasts

“…As described above, both sexual agglutination and G1 -arrest are specifically regulated by diffusible sex pheromones secreted by the opposite mating type cells in S. cerevisiue (see reviews of THORNER 1981 andSPRAGUE et al 1983). MCCULLOUGH and HERSKOWITZ (1979) clearly showed the interspecies' action of sex pheromones in S. cerevisiae and S. kluyveri. We tried to extend this analysis to other non-conventional yeasts.…”