Open AccessRhizosphere Competitiveness of Trichloroethylene-Degrading, Poplar-Colonizing Recombinant Bacteria
Author(s) -
Hyungbo Shim,
Sanjay Chauhan,
Doohyun Ryoo,
Kally Bowers,
Stuart M. Thomas,
Keith A. Canada,
Joel G. Burken,
Thomas K. Wood
Publication year - 2000
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.66.11.4673-4678.2000
Subject(s) - rhizosphere , bacteria , biology , rhizobium , burkholderia , pseudomonas , botany , rhizobiaceae , microbiology and biotechnology , colonization , pseudomonadaceae , symbiosis , genetics
Indigenous bacteria from poplar tree (Populus canadensis var.eugenei ‘Imperial Carolina’) and southern California shrub rhizospheres, as well as two tree-colonizingRhizobium strains (ATCC 10320 and ATCC 35645), were engineered to express constitutively and stably tolueneo -monooxygenase (TOM) fromBurkholderia cepacia G4 by integrating thetom locus into the chromosome. The poplar andRhizobium recombinant bacteria degraded trichloroethylene at a rate of 0.8 to 2.1 nmol/min/mg of protein and were competitive against the unengineered hosts in wheat and barley rhizospheres for 1 month (colonization occurred at a level of 1.0 × 105 to 23 × 105 CFU/cm of root). In addition, six of these recombinants colonized poplar roots stably and competitively with populations as large as 79% ± 12% of all rhizosphere bacteria after 28 days (0.2 × 105 to 31 × 105 CFU/cm of root). Furthermore, five of the most competitive poplar recombinants (e.g., Pb3-1 and Pb5-1, which were identified asPseudomonas sp. strain PsK recombinants) retained the ability to express TOM for 29 days as 100% ± 0% of the recombinants detected in the poplar rhizosphere expressed TOM constitutively.