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Isolation and characterization of Bradyrhizobium sp. SR1 degrading two β-triketone herbicides

Romdhane, Sana and Devers-Lamrani, Marion and Martin-Laurent, Fabrice and Calvayrac, Christophe and Rocaboy-Faquet, Emilie and Riboul, David and Cooper, Jean-François and Barthelmebs, Lise Isolation and characterization of Bradyrhizobium sp. SR1 degrading two β-triketone herbicides. (2015) Environmental Science and Pollution Research. 1-11. ISSN 0944-1344

(Document in English)

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Official URL: http://dx.doi.org/10.1007/s11356-015-4544-1


In this study, a bacterial strain able to use sulcotrione,a β-triketone herbicide, as sole source of carbon and energy was isolated from soil samples previously treated with this herbicide. Phylogenetic study based on16S rRNA gene sequence showed that the isolate has 100 % of similarity with several Bradyrhizobium and was accordingly designated as Bradyrhizobium sp. SR1. Plasmid profiling revealed the presence of a large plasmid (>50 kb) in SR1 not cured under nonselective conditions. Its transfer to Escherichia coli by electroporation failed to induce β-triketone degrading capacity,suggesting that degrading genes possibly located on this plasmid cannot be expressed in E. coli or that they are not plasmid borne. The evaluation of the SR1 ability to degrade various synthetic (mesotrione and tembotrione) and natural (leptospermone) triketones showed that this strain was also able to degrademesotrione. Although SR1 was able to entirely dissipate both herbicides, degradation rate of sulcotrione was ten times higher than that of mesotrione, showing a greater affinity of degrading-enzyme system to sulcotrione. Degradation pathway of sulcotrione involved the formation of 2-chloro-4-mesylbenzoic acid (CMBA), previously identified in sulcotrione degradation, and of a new metabolite identified as hydroxy-sulcotrione.Mesotrione degradation pathway leads to the accumulation of-methylsulfonyl-2-nitrobenzoic acid(MNBA) and 2-amino-4 methylsulfonylbenzoic acid(AMBA), two well-known metabolites of this herbicide. Along with the dissipation of β-triketones, one could observe the decrease in 4-hydroxyphenylpyruvate dioxygenase(HPPD) inhibition, indicating that toxicity was due to parent molecules, and not to the formed metabolites. This is the first report of the isolation of bacterial strain able to transform two β-triketones.

Item Type:Article
Additional Information:Thanks to Springer Verlag. The definitive version is available at http://link.springer.com The original PDF of the article can be found at Environmental Science and Pollution Research website : http://link.springer.com/article/10.1007%2Fs11356-015-4544-1
HAL Id:hal-01204955
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:Other partners > Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement - AgroSup Dijon (FRANCE)
French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
French research institutions > Institut National de la Recherche Agronomique - INRA (FRANCE)
Other partners > Université de Bourgogne - UB (FRANCE)
Other partners > Université Pierre et Marie Curie, Paris 6 - UPMC (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
Other partners > Université de Perpignan Via Domitia - UPVD (FRANCE)
Laboratory name:
Deposited On:24 Sep 2015 15:29

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