Intergeneric hybrids between Saccharomycopsis fibuligera and Yarrowia lipolytica

Abstract

Summary: Saccharomycopsis fibuligera can utilize starch but not tributyrin as the sole carbon source, whereas Yarrowia lipolytica can utilize tributyrin but not starch. S. fibuligera mutant strain 193 met was crossed to Y. lipolytica A his1 to produce hybrids. The intergeneric hybrids were able to utilize both starch and tributyrin as sole carbon source. They were mitotically unstable and gave segregants during prolonged vegetative culture. The majority of these segregants had the phenotype of the S. fibuligera parent, with a very low number of genetic recombinants. A more stable hybrid was produced by protoplast fusion between a mutant, ade met, obtained from UV treatment of a Met− mitotic segregant of the hybrid 14i and Y. lipolytica B lys5 leu2 ade1 xpr2. Sixteen of the 40 mitotic segregants of this hybrid were recombinants. Furthermore when a haploid mitotic segregant of S. fibuligera 193 met, met glu, was crossed to Y. lipolytica B leu2 ade1 xpr2 more stable hybrids were also obtained. Eleven of the 35 mitotic segregants of the hybrid SA11 were recombinants. Such high frequencies of recombinant sectors from these hybrids should provide a system to establish genetic mapping analysis for the novel Saccharomycopsis-Yarrowia recombinant strains.