Fusion of Yeast Protoplasts Induced by Polyethylene Glycol

Abstract

Protoplasts, prepared from auxotrophic strains of Saccharomyces cerevisiae, Schizosaccharomyces pombe and Hansenula wingei, were mixed to give intraspecific complementary combinations. Polyethylene glycol (PEG) was added to induce agglutination and fusion. Some of the fused products grew on the surface of solid minimal medium forming large vacuolated bodies. Others reverted to hybrid cells when embedded in solid minimal regeneration medium. The cytological and preliminary genetical analyses suggest a synkaryon formation and integration of genetic markers from parental strains. The frequency of intrageneric fusions assessed from the number of protoplasts growing on the surface of minimal agar was estimated to be 1-3%, while the frequency of hybrid colony formation in regeneration medium was less than 1%.