title: Plant protection by the recombinant, root-colonizing Pseudomonas fluorescens F113rifPCB strain expressing arsenic resistance: improving rhizoremediation.
abstract: OBJECTIVE
  The present study was designed to evaluate the stable insertion and expression of an arsenic resistance operon in the rhizosphere competent, PCB degrading strain Pseudomonas fluorescens F113rifPCB (F113rifPCB) and to investigate its ability to protect plants from arsenic.
  
  
  RESULTS
  Introduction of the clone pUM3 (arsRDABC) into F113rifPCB was carried out by triparental conjugation. The resultant arsenic resistant strain was screened through a number of phenotypic tests including ability to grow on biphenyl, its rhizosphere competence and plant protection potential.
  
  
  CONCLUSIONS
  Insertion and expression of arsenic resistant operon arsRDABC (from plasmid R773) into F113rifPCB strain has allowed this strain to grow, colonize the root and degrade biphenyl (100 mmol l(-1)) in the presence of sodium arsenate concentrations of up to 11.5 mmol l(-1). The strain retains its ability to colonize the rhizosphere of plants and appears to provide seed germination protection to arsenic which is not seen by the wild type.
  
  
  CONCLUSIONS
  Owing to the significantly improved growth characteristics of both this rhizobacterium and plant species, the use of F113rifPCB-ars endowed with arsenic resistance capabilities may be a promising strategy to remediate mixed organic metal-contaminated sites. These types of strain could be used in the inoculation of metal accumulation plants for phytoremediation.
authors.affiliation: Department of Science and Health, Institute of Technology Carlow, Carlow, Ireland.
authors.forename: R P
authors.initials: RP
authors.lastname: Ryan
authors.forename: D
authors.initials: D
authors.lastname: Ryan
authors.forename: D N
authors.initials: DN
authors.lastname: Dowling
mesh_terms: D001151:Arsenic / Q000378:metabolism / Q000633:toxicity*; D001673:Biodegradation, Environmental; D001711:Biotransformation / Q000502:physiology; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D018525:Germination / Q000187:drug effects; D009876:Operon; D063245:Plant Development; D018517:Plant Roots / Q000382:microbiology*; D010944:Plants / Q000187:drug effects* / Q000382:microbiology; D011078:Polychlorinated Biphenyls / Q000378:metabolism; D011551:Pseudomonas fluorescens / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*
chemical_list: D011078:Polychlorinated Biphenyls; D001151:Arsenic