Etude de l'évolution du potentiel génétique de populations bactériennes dégradant l'atrazine
type: Dataset
description: Atrazine, one of the most used herbicide to control the development of weeds in crop, has led to the contamination of the environment. Repeated exposure to this herbicide resulted in the emergence of microbial populations able to degrade atrazine and to use it as a nitrogen source for its growth. These microbial populations are responsible for accelerated biodegradation of atrazine (BDA), a key ecosystemic service diminishing the persistence of this herbicide in the environment. The aim of this PhD work was to study genetic and physiological mechanisms responsible for functioning and improving of this ecosystemic service. We applied an experimental approach starting from genes to communities degrading atrazine in order to identify processes of adaptation involved in the evolution of accelerated biodegradation function.The first part of the PhD aimed at evaluating the importance of accumulation of single mutations in the atzA gene for the activity of AtzA transforming atrazine to hydroxyatrazine. Sequencing or atzA genes amplified from different atrazine-degrading isolates (Pseudomonas sp. ADP WT, Pseudomonas sp. ADP Ps and differents Chelatobacter heintzii) showed that atzA sequence was conserved. However, four non synonymous mutations were identified (1 for Pseudomonas sp. ADP Ps and 3 for Chelatobacter heintzii). Modeling of AtzA structure showed that three mutations were located in important regions (active site, interaction with atrazine and with the metal Fe2+). [...] The second part aimed at studying the plasticity of the atrazine-degrading pathway in two opposed conditions: (i) one aiming at evaluating the persistence of degrading capability in absence of selection pressure and (ii) a second one aiming at evaluating the evolution of degrading capability under high selection pressure exerted by atrazine. With these aims, experimental evolutions were carried out with Pseudomonas sp. ADP. (i) We showed that cyanuric acid exposure led to the selection of a newly-…
landing page: https://theses.hal.science/tel-00806324
identifier: NNT: 2011DIJOS099
keyword: atrazine
keyword: atz-gene
keyword: biodegradation
keyword: evolution-experimentale
keyword: experimental-evolution
keyword: gene-atz
keyword: infoeu-reposemanticsdoctoralthesis
keyword: insertion-sequence
keyword: sdvsalife-sciences-q-bioagricultural-sciences
keyword: sequences-dinsertion
keyword: theses
issued: 2026-05-11T20:39:36.988651
modified: 2026-05-11T20:39:36.988656
language: fr
contact point: Organization
  fn: CCSD

test_moissonnage_selune
type: Agent

Etude de l'évolution du potentiel génétique de populations bactériennes dégradant l'atrazine
type: Distribution
format: HTML
access URL: https://theses.hal.science/tel-00806324
issued: 2026-05-11T20:39:37.068584
modified: 2026-05-11T20:39:36.957562