caa a22 4500 397552947 CHVBK 20180308164755.0 cr unu---uuuuu 161202e199606 xx s 000 0 eng 10.1111/j.1574-6941.1996.tb00307.x doi (NATIONALLICENCE)oxford-10.1111/j.1574-6941.1996.tb00307.x Rhizosphere effects on biodegradation of 2,5-dichlorobenzoate by a bioluminescent strain of root-colonizing Pseudomonas fluorescens [Elektronische Daten] [David E. Crowley, Maria V. Brennerova, Cathy Irwin, Vladimir Brenner, Dennis D. Focht] A recombinant strain of bioluminescent Pseudomonas fluorescens 2-79 RLD containing a catabolic pathway for degradation of 2,5-dichlorobenzoate (2,5-DCB) was monitored in soil microcosms to examine the influence of plants on its growth and activity in a contaminated soil. Recombinant P. fluorescens 2-79 RLD was generated by mating a versatile chlorobenzoate utilizer, P. putida P 111, containing plasmid pPB111, with a bioluminescent strain of P. fluorescens that had been transformed previously with a Tn7-luxCDABE marker. Plasmid pPB111 contains genes encoding for a chlorobenzoate-1,2-dioxygenase that converts ortho-chlorobenzoates to their corresponding catechols. DNA hybridization experiments and cell-free extract assays with parental and recombinant P. fluorescens 2-79 RLD suggested that the reaction product of the plasmid pPB111 encoded chlorobenzoate dioxygenase was degraded by an endogenous catechol dioxygenase in P. fluorescens 2-79. After introduction of P. fluorescens 2-79 RLD into soil containing 10 mg kg−1 2,5-DCB, normally recalcitrant 2,5-DCB was degraded rapidly over a period of 2 to 4 days in soil with plants. In contrast, 2,5-DCB disappearance in nonplanted soil was significantly slower, requiring 7 days in one experiment, and more than 2 weeks in a second experiment. Population numbers of the degrader were similar in planted and nonplanted soil for the first 7 days, but declined in nonplanted soils by day 14. Physiological status, measured using an assay based on lag-phase duration, was similar in planted and nonplanted soils at day 2, but rapidly declined in nonplanted soil by day 7. At day 14, plasmid stability in P. fluorescens 2-79 RLD was significantly greater in rhizosphere soil; only 10% of P. fluorescens 2-79 RLD cells in rhizosphere soil had lost the ability to degrade 2,5-DCB, versus 94% of the cells in nonplanted soil. The plasmid also was transferred to indigenous bacteria in both planted and nonplanted soils, as determined by the appearance of novel degraders. The results demonstrate that the presence of plants promoted rapid degradation of DCB and provided a niche that enhanced maintenance of plasmid pPB111 in the degrader bacterium. © 1996 Federation of European Microbiological Societies. All rights reserved Conjugation nationallicence Gene transfer nationallicence lux marker nationallicence Plasmid nationallicence Physiological status nationallicence Phytoremediation nationallicence Crowley David E. Department of Soil and Environmental Sciences, University of California, Riverside, CA 92521, USA aut Brennerova Maria V. Department of Soil and Environmental Sciences, University of California, Riverside, CA 92521, USA aut Irwin Cathy Department of Soil and Environmental Sciences, University of California, Riverside, CA 92521, USA aut Brenner Vladimir Department of Soil and Environmental Sciences, University of California, Riverside, CA 92521, USA aut Focht Dennis D. Department of Soil and Environmental Sciences, University of California, Riverside, CA 92521, USA aut FEMS Microbiology Ecology Blackwell Publishing Ltd 20/2(1996-06), 79-89 20:2<79 1996 20 femsec https://doi.org/10.1111/j.1574-6941.1996.tb00307.x text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1111/j.1574-6941.1996.tb00307.x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Crowley David E. Department of Soil and Environmental Sciences, University of California, Riverside, CA 92521, USA aut NATIONALLICENCE 700 1- Brennerova Maria V. Department of Soil and Environmental Sciences, University of California, Riverside, CA 92521, USA aut NATIONALLICENCE 700 1- Irwin Cathy Department of Soil and Environmental Sciences, University of California, Riverside, CA 92521, USA aut NATIONALLICENCE 700 1- Brenner Vladimir Department of Soil and Environmental Sciences, University of California, Riverside, CA 92521, USA aut NATIONALLICENCE 700 1- Focht Dennis D. Department of Soil and Environmental Sciences, University of California, Riverside, CA 92521, USA aut NATIONALLICENCE 773 0- FEMS Microbiology Ecology Blackwell Publishing Ltd 20/2(1996-06), 79-89 20:2<79 1996 20 femsec Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford