Factors Affecting Recombinant Frequency in Protoplast Fusions of Streptomyces coelicolor

Abstract

The optimum concentration of polyethylene glycol 1000 (PEG) for the production of recombinants through protoplast fusion in S. coelicolor was about 50% (wt/vol). The addition of 14% (vol/vol) dimethyl sulfoxide to the fusion mixture enhanced recombination frequencies, but only at sub-optimal PEG concentrations. After treatment of protoplasts with 50% PEG for 1 min, the frequency of recombinants in a multi-factor cross sometimes exceeded 20% of the total progeny. The frequency of recombinants in the progeny could be significantly enhanced by UV irradiation of the parental protoplast suspensions immediately before fusion.