|Pileggi, S. Veiga|
|Garbugio Da Silva, P|
Submitted to: Chemosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/16/2011
Publication Date: 1/13/2012
Publication URL: http://hdl.handle.net/10113/55073
Citation: Pileggi, M., Pileggi, S., Olchanheski, L.R., Garbugio Da Silva, P.A., Munoz, A.M., Koskinen, W.C., Barber, B.L., Sadowsky, M.J. 2012. Isolation of mesotrione-degrading bacteria from aquatic environments in Brazil. Chemosphere. 86(11):1127-1132. Interpretive Summary: In this study we report on the isolation of a Pantoea ananatis strain that completely degraded mesotrione by a pathway what does not produce 2-amino-4-methylsulfonyl benzoic acid or 4-methylsulfonyl-2-nitrobenzoic acid, two metabolites previously identified in a mesotrione-degrading Bacillus strain. The bacterium was isolated from water environments surrounded by mesotrione treated fields. To our knowledge, this is the first report of P. ananatis being involved in pesticide degradation although Pantoea sp strains have previously been reported to be associated with animal and plant diseases, can readily be found in the environment. Results of this study may lead to a better understanding about the fate of mesotrione in water. Also, since P. ananatis rapidly degraded mesotrione, likely through cometabolic processes, this strain might be useful for bioremediation purposes.
Technical Abstract: Mesotrione is a benzoylcyclohexane-1,3-dione herbicide that inhibits 4-hydroxyphenyl pyruvate dioxygenase (HPPD) in target plants. Although it has been used since 2000, only a limited number of degrading microorganisms have been reported. Mesotrione-degrading bacteria were selected among strains isolated from Brazilian aquatic environments, located near corn fields treated with this herbicide. Pantoea ananatis was found to rapidly and completely degrade mesotrione. Mesotrione did not serve as a sole C, N, or S source for growth of P. ananatis, and mesotrione catabolism required glucose supplementation to minimal media. LC/MS/MS analyses indicated that mesotrione degradation produced intermediates other than 2-amino-4-methylsulfonyl benzoic acid (AMBA) or 4-methylsulfonyl-2-nitrobenzoic acid (MNBA), two metabolites previously identified in a mesotrione-degrading Bacillus strain. Since P. ananatis rapidly degraded mesotrione, likely through cometabolic processes, this strain might be useful for bioremediation purposes.