Phenotypic characteristics of bacillus subtilis mutants with decreased activity of exonuclease i

A Bacillus subtilis strain containing a mutation decreasing exonuclease I activity by up to 25% as compared to normal cells of the original BD46 strain was developed. A decrease in B. subtilis exonuclease I activity increased the sensitivity of mutant cells to UV irradiation and mitomycin C, decreased the frequency of recombination during chromosomal transduction and transformation, decreased the frequency of transposon Tn9/7 translocation from plasmid to the bacterial chromosome, and did not affect the frequency of plasmid transformation. The corresponding mutation was mapped