[Plasmid transformation and transduction in different rec-mutants of Bacillus subtilis]

The ability of different Bacillus subtilis rec mutants for transformation and transduction by plasmid DNA and influence of these mutations on plasmid recombination was studied. The efficiency of plasmid transformation was found to be decreased in most cases. Plasmid transduction depended slightly on any rec mutation in recipient cells. When rec mutants carrying pUB110 plasmid were transformed with pBD12 DNA which is homologous to the resident plasmid, different values fo "marker rescue" were observed. Several strains demonstrate the effect similar to that in recombination-proficient strains, while others exhibit the decreased values or no effect at all. These results indicate that plasmid and chromosomal recombination have common recombinational steps, though there are also some differences in both types of recombination.