Polyethylene glycol centrifugal fusion between Pleurotus ostreatus and Pleurotus sajor-caju

Protoplasts from the monokaryotic mycelia of an auxotrophic mutant of Pleurotus ostreatus (Jacq.: Pr.) Kummer. and Pleurotus sajor-caju Singer. were prepared using optimum conditions for their release. The polyethylene glycol (PEG) and the PEG centrifugal fusion methods were evaluated for the fusions of protoplasts. Results showed that the rate of fusion using the later method was about 10% greater than with the former method. The mycelial growths of the fused strains obtained by the later method showed no remarkable differences in the growth rate and:the mycelial density compared with those of the parent strains. However, paired culture tests and isozyme analyses revealed that the fusant produced from P. ostreatus and P. sajor-caju using the PEG centrifugal fusion methods is a strain distinctly different from its parent strains. The fusant did not produced fruiting bodies during the initial fruiting test.