Genetic recombination in the cephamycin producer, Streptomyces clavuligerus

In order to study the mechanism of cephamycin production by streptomycetes and to use genetic recombination in strain development, we undertook genetic studies in Streptomyces lipmanii and S. clavuligerus. S. lipmanii crosses gave 0.005-1.3% "prototroph-like" colonies, but all segregated back to parental genotypes. Crosses of S. clavuligerus resulted in lower frequencies of "prototroph-like" colonies, i.e., 0.00002-0.9%. In ade x ura and ade x his crosses, the recombinant progeny did not segregate back. In arg x ade and arg x his crosses, segregation occurred in about 50% of the progeny. These data demonstrate that true haploid recombinants occur in crosses of S. clavuligerus. S. lipmanii yielded only heterokaryons and, therefore, is less suitable than S. clavuligerus for further genetic study.