Fusion of protoplasts of Streptomyces lavendulae

Protoplasts of two different auxotrophic mutants of Streptomyces lavendulae were fused with polyethylene glycol (PEG) 1,000, and allowed to regenerate on selective media. Prototrophic colonies overwhelmed other types of recombinants on any selective media. These prototrophic strains were stable after successive isolation. These results suggest that stable diploid cells were formed by cell fusion, which differed from the case of S. coelicolor.