0000000001268872
AUTHOR
Frédérique Changey
In vitro evolution of an atrazine-degrading population under cyanuric acid selection pressure: Evidence for the selective loss of a 47kb region on the plasmid ADP1 containing the atzA, B and C genes
International audience; The adaptation of microorganisms to pesticide biodegradation relies on the recruitment of catabolic genes by horizontal gene transfer and homologous recombination mediated by insertion sequences (IS). This environment-friendly function is maintained in the degrading population but it has a cost which could diminish its fitness. The loss of genes in the course of evolution being a major mechanism of ecological specialization, we mimicked evolution in vitro by sub-culturing the atrazine-degrading Pseudomonas sp. ADP in a liquid medium containing cyanuric acid as the sole source of nitrogen. After 120 generations, a new population evolved, which replaced the original on…
Evolution of genetic degradation potential of pesticide-degrading bacterial communities
International audience
Étude de l’évolution du potentiel génétique de populations bactériennes dégradant l’atrazine
17 pages de références bibliographiques et 20 pages d'annexes; L’atrazine, un des herbicides les plus utilisés pour contrôler le développement des plantes adventices dans les cultures, a conduit à la contamination de l’environnement. L’exposition chronique à cet herbicide a conduit à l’émergence de populations microbiennes du sol capables de dégrader l’atrazine et de l’utiliser comme une source d’azote pour leur croissance. Ces populations microbiennes sont responsables de la biodégradation accélérée (BDA) de l’atrazine, un service écosystémique contribuant à diminuer la persistance de cet herbicide dans l’environnement. L’objectif de ce travail était d’étudier les mécanismes génétiques et …
Importance of genetic plasticity for microbial adaptation to pesticide biodegradation: in vitro evolution of Pseudomonas sp. ADP under atrazine or cyanuric acid selection pressure as case studies
International audience
Genetic plasticity of atrazine-degrader: evidence for the deletion of atzABC genes in pseudomonas sp. adp in response to cyanuric acid selection pressure
International audience; Several bacterial strains are known to metabolize s-triazines herbicides among which atrazine reported worldwidel to contaminate soil and water resources. The complete mineralization of atrazine to carbon dioxide and ammonium is catalyzed by 6 hydrolytic enzymes encoded by atzABCDEF genes located on the plasmid pADP1 in Pseudomonas ADP. The atzABC genes code for the upper pathway transforming atrazine to cyanuric acid, while the atzDEF genes code for the lower pathway transforming cyanuric acid to simple compounds. In order to study the genetic plasticity of the atrazine catabolic pathway, we performed an in vitro evolution study consisting in applying a continuous s…
Evidence of atrazine mineralization in a soil from the Nile Delta: Isolation of Arthrobacter sp. TES6, an atrazine-degrading strain
International audience; The s-triazine herbicide atrazine was rapidly mineralized (i.e., about 60% of C-14-ring-labelled atrazine released as (CO2)-C-14 within 21 days) by an agricultural soil from the Nile Delta (Egypt) that had been cropped with corn and periodically treated with this herbicide. Seven strains able to degrade atrazine were isolated by enrichment cultures of this soil. DNA fingerprint and phylogenetic studies based on 165 rRNA analysis showed that the seven strains were identical and belonged to the phylogeny of the genus Arthrobacter (99% similarity with Arthrobacter sp. AD38, EU710554). One strain, designated Arthrobacter sp. strain TES6, degraded atrazine and mineralized…
Processes involved in the adaptation of soil microbiota to enhance biodegradation of pesticides: atrazine-degrading community as a study case
International audience