Role of IncP-1? plasmids pWDL7::rfp and pNB8c in chloroaniline catabolism as determined by genomic and functional analyses. Academic Article uri icon

Overview

abstract

  • Broad-host-range catabolic plasmids play an important role in bacterial degradation of man-made compounds. To gain insight into the role of these plasmids in chloroaniline degradation, we determined the first complete nucleotide sequences of an IncP-1 chloroaniline degradation plasmid, pWDL7::rfp and its close relative pNB8c, as well as the expression pattern, function, and bioaugmentation potential of the putative 3-chloroaniline (3-CA) oxidation genes. Based on phylogenetic analysis of backbone proteins, both plasmids are members of a distinct clade within the IncP-1? subgroup. The plasmids are almost identical, but whereas pWDL7::rfp carries a duplicate inverted catabolic transposon, Tn6063, containing a putative 3-CA oxidation gene cluster, dcaQTA1A2BR, pNB8c contains only a single copy of the transposon. No genes for an aromatic ring cleavage pathway were detected on either plasmid, suggesting that only the upper 3-CA degradation pathway was present. The dcaA1A2B gene products expressed from a high-copy-number vector were shown to convert 3-CA to 4-chlorocatechol in Escherichia coli. Slight differences in the dca promoter region between the plasmids and lack of induction of transcription of the pNB8c dca genes by 3-CA may explain previous findings that pNB8C does not confer 3-CA transformation. Bioaugmentation of activated sludge with pWDL7::rfp accelerated removal of 3-CA, but only in the presence of an additional carbon source. Successful bioaugmentation requires complementation of the upper pathway genes with chlorocatechol cleavage genes in indigenous bacteria. The genome sequences of these plasmids thus help explain the molecular basis of their catabolic activities.

publication date

  • June 13, 2012

Research

keywords

  • Aniline Compounds
  • Carbon
  • Catechols
  • Cluster Analysis
  • DNA Transposable Elements
  • DNA, Bacterial
  • Escherichia coli
  • Gene Expression Profiling
  • Gene Expression Regulation, Bacterial
  • Metabolic Networks and Pathways
  • Molecular Sequence Data
  • Multigene Family
  • Oxidation-Reduction
  • Phylogeny
  • Promoter Regions, Genetic
  • Sequence Analysis, DNA
  • Transcription, Genetic

Identity

PubMed ID

  • 22101050

Additional Document Info

start page

  • 828

end page

  • 838

volume

  • 78

issue

  • 3