title: Evolution of the IncP-7 carbazole-degradative plasmid pCAR1 improves survival of its host Pseudomonas fluorescens Pf0-1 in artificial water microcosms.
abstract: In our previous study, Pseudomonas fluorescens Pf0-1L, harbouring the IncP-7 carbazole-degradative plasmid pCAR1 : : rfp, was shown to be undetectable within 5 days post-inoculation in carbazole-contaminated artificial freshwater microcosms containing several plasmid-free bacteria in addition to Pf0-1L(pCAR1 : : rfp). Fourteen days after the inoculation, carbazole degraders become detectable. Here, we revealed that these isolates were not pCAR1 transconjugants, but Pf0-1L(pCAR1 : : rfp) mutants, based on RFLP and BOX-A1R-based repetitive extragenic palindromic-PCR (BOX-PCR) analysis. Notably, the mutants displayed more rapid initiation of carbazole degradation than the parent strain Pf0-1L(pCAR1 : : rfp). The mutants were unable to degrade anthranilate due to a 163 bp deletion in the antA gene, which was overcome by their transformation with a wild-type antABC-expressing plasmid. Quantitative RT-PCR analysis indicated that the transcriptional induction of carbazole-, anthranilate- and catechol-degradative genes was comparable in both parent and mutant strains. The deletion mutants became dominant in the artificial water microcosm. The mutation caused anthranilate to accumulate instead of catechol, a toxic compound for the parent strain, and may be beneficial to host survival in artificial microcosms.
authors.affiliation: Japan Collection of Microorganisms, BioResource Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.|Biotechnology Research Center, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Shintani
authors.affiliation: Biotechnology Research Center, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Tadafumi
authors.initials: T
authors.lastname: Horisaki
authors.affiliation: Biotechnology Research Center, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Hisakazu
authors.initials: H
authors.lastname: Yamane
authors.affiliation: Japan Collection of Microorganisms, BioResource Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Moriya
authors.initials: M
authors.lastname: Ohkuma
authors.affiliation: Biotechnology Research Center, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Nojiri
mesh_terms: D001711:Biotransformation; D002227:Carbazoles / Q000378:metabolism* / Q000633:toxicity; D002273:Carcinogens / Q000378:metabolism* / Q000633:toxicity; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D019143:Evolution, Molecular; D017353:Gene Deletion; D020869:Gene Expression Profiling; D050296:Microbial Viability / Q000187:drug effects*; D008969:Molecular Sequence Data; D058889:Molecular Typing; D009154:Mutation; D010957:Plasmids; D012150:Polymorphism, Restriction Fragment Length; D011551:Pseudomonas fluorescens / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014871:Water Microbiology; D062367:ortho-Aminobenzoates / Q000378:metabolism
chemical_list: D002227:Carbazoles; D002273:Carcinogens; D004269:DNA, Bacterial; D062367:ortho-Aminobenzoates; C041514:carbazole; C031385:anthranilic acid