Applied and Environmental Microbiology · 2000 · 63 citations · 17 references
AgricultureMicrobiologyPlant BiologyMicrobial EcologyPlant-microbe InteractionsSoil MicrobiologyRhizosphere BiologyRhizosphere ColonizationRhizosphere EcologyRhizosphere InteractionsRhizosphere MicrobiologyRhizosphere ProcessesMicrobial Competition In The RhizosphereMicrobial CompetitivenessRhizosphere Bacterial CommunitiesRhizosphere CompetenceRhizosphere CompetitionRhizosphere FitnessRhizosphere Microbial EcologyRhizosphere Microbial Interactions
Indigenous bacteria from poplar tree (Populus canadensis var. eugenei 'Imperial Carolina') and southern California shrub rhizospheres, as well as two tree-colonizing Rhizobium strains (ATCC 10320 and ATCC 35645), were engineered to express constitutively and stably toluene o-monooxygenase (TOM) from Burkholderia cepacia G4 by integrating the tom locus into the chromosome. The poplar and Rhizobium 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 x 10(5) to 23 x 10(5) 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 x 10(5) to 31 x 10(5) CFU/cm of root). Furthermore, five of the most competitive poplar recombinants (e.g., Pb3-1 and Pb5-1, which were identified as Pseudomonas 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.
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