Requirement of DNA repair mechanisms for survival of Burkholderia cepacia G4 upon degradation of trichloroethylene

A Tn5-based mutagenesis strategy was used to generate a collection of trich loroethylene (TCE)-sensitive (TCS) mutants in order to identify repair syst ems or protective mechanisms that shield Burkholderia cepacia G4 from the t oxic effects associated with TCE oxidation. Single Tn5 insertion sites were mapped within open reading frames putatively encoding enzymes involved in DNA repair (UvrB, RuvB, RecA, and RecG) in 7 of the 11 TCS strains obtained (4 of the TCS strains had a single Tn5 insertion within a uvrB homolog). T he data revealed that the uvrB-disrupted strains were exceptionally suscept ible to killing by TCE oxidation, followed by the recA strain, while the ru vB and recG strains were just slightly more sensitive to TCE than the wild type. The uvrB and recA strains were also extremely sensitive to UV light a nd, to a lesser extent, to exposure to mitomycin C and H2O2. The data from this study establishes that there is a link between DNA repair and the abil ity of B. cepacia G4 cells to survive following TCE transformation. A possi ble role for nucleotide excision repair and recombination repair activities in TCE-damaged cells is discussed.