ISSN:
0006-3592
Keywords:
plant-microbial associations
;
2,4-D
;
biodegradation
;
plant protection
;
Dolichos lablab
;
cotton
;
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
A significant “biosafening” protection of plants from the effect of 2,4-D in plant-microbial associations has been demonstrated in this study. The 2,4-D-degrading plasmid, pJP4 was transferred into Rhizobium sp. CB1024, which nodulates Dolichos lablab, and Azospirillum brasilense Sp7 carrying a nifA-lacZ gene marker, which can colonize cotton roots. Both transconjugants degraded 2,4-D in pure culture via cometabolism up to 50 μg mL-1. When the transconjugants were inoculated onto Dolichos lablab and cotton, respectively, such plants were resistant to this herbicide when the nutrient solution was treated with 2,4-D up to 10 μg mL-1 for Dolichos lablab and 0.5 μg mL-1 for cotton. Plants inoculated with wild-type strains were dead (Dolichos lablab) or dying (cotton). Because cotton is more sensitive to herbicides, only incomplete protection of plants was achieved with the transconjugant. Improving the effect of colonization of Azospirillum on cotton roots may be critical for a complete degradation and plant protection. The transconjugant of Rhizobium sp. CB1024 was still able to nodulate Dolichos lablab, N2-fixing activity was only slightly affected. Other pesticide-degrading capacities may also be inserted into those plant-associated bacterial strains for the degradation of these chemicals by plant-microbial associations. Whether such systems will be successful when applied in the field with competition from other bacteria is being examined. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 53: 513-519, 1997.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
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