HAL Id: hal-02736786
https://hal.inrae.fr/hal-02736786
Submitted on 2 Jun 2020
HAL is a multi-disciplinary open access
archive for the deposit and dissemination of
sci-entific research documents, whether they are
pub-lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.
L’archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d’enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.
Isolation and characterization of β-triketone herbicides
degrading bacteria isolated from an arable soil
Lise Barthelmebs, Sana Romdhane, Marion Devers-Lamrani, Cédric Bertrand,
Fabrice Martin-Laurent
To cite this version:
FEMS7-1144
Environmental Microbiology/Microbial Ecology /Microbial Communities
ISOLATION AND CHARACTERIZATION OF Β-TRIKETONE HERBICIDES DEGRADING BACTERIA ISOLATED FROM AN ARABLE SOIL
L. Barthelmebs1, S. Romdhane1, M. Devers-lamrani2, C. Bertrand3, F. Martin-laurent2
1University UPVD, BAE, Perpignan CEDEX, France
2INRA, Agroecology, Dijon, France
3University UPVD, CNRS, Perpignan CEDEX, France
Backgrounds
Microbial degradation is considered as the major process involved in the elimination of pesticides in the environment.
Objectives
In this context, our work aims to study the role of soil bacteria in the degradation of synthetic and natural β-triketone herbicides and to elucidate genetic mechanisms involved in their
biotransformations. Methods
Therefore, a microcosm approach was performed using an agricultural soil, in order to isolate bacterial strains capable of degrading β-triketone herbicides.
Conclusions
Two bacterial strains were isolated : Bradyrhizobium sp. SR1 able to degrade sulcotrione and mesotrione, two synthetic herbicides, and Methylophilus sp. LS1 degrading leptospermone, a natural one. The metabolism of these compounds was studied showing that their biodegradations resulted in the formation of several metabolites previously described in the literature, such as
2-chloro-4-mesylbenzoic acid, 4-methylsulfonyl-2-nitrobenzoic acid and 2-amino-4 methylsulfonylbenzoic acid from the two synthetic compounds, but also of two new metabolites identified as hydroxy-sulcotrione from sulcotrione and hydroxy-leptospermone from leptospermone.
In order to characterize degradation genes from Bradyrhizobium sp. SR1, a library of 14 000 mutants was constructed allowing the selection of two Sul- mutants. The interrupted genes didn’t code for sulcotrione degradation enzymes, but for transcriptional regulatory genes potentially involved in the regulation of stress. In the case of mesotrione, a nonspecific system involving a nitroreductase was identified. For leptospermone, the natural herbicide, degradation by Methylophilus sp. LS1 was most likely supported by a nonspecific system.
