title: Interactions of earthworms with Atrazine-degrading bacteria in an agricultural soil.
abstract: In the last 10 years, accelerated mineralization of Atrazine (2-chloro-ethylamino-6-isopropylamino-s-triazine) has been evidenced in agricultural soils repeatedly treated with this herbicide. Here, we report on the interaction between earthworms, considered as soil engineers, and the Atrazine-degrading community. The impact of earthworm macrofauna on Atrazine mineralization was assessed in representative soil microsites of earthworm activities (gut contents, casts, burrow linings). Soil with or without earthworms, namely the anecic species Lumbricus terrestris and the endogenic species Aporrectodea caliginosa, was either inoculated or not inoculated with Pseudomonas sp. ADP, an Atrazine-degrading strain, and was either treated or not treated with Atrazine. The structure of the bacterial community, the Atrazine-degrading activity and the abundance of atzA, B and C sequences in soil microsites were investigated. Atrazine mineralization was found to be reduced in representative soil microsites of earthworm activities. Earthworms significantly affected the structure of soil bacterial communities. They also reduced the size of the inoculated population of Pseudomonas sp. ADP, thereby contributing to the diminution of the Atrazine-degrading genetic potential in representative soil microsites of earthworm activities. This study illustrates the regulation produced by the earthworms on functional bacterial communities involved in the fate of organic pollutants in soils.
authors.affiliation: CNRS/Université de Rennes 1, UMR 6553 ECOBIO, IFR CAREN, Rennes, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Kersanté
authors.forename: Fabrice
authors.initials: F
authors.lastname: Martin-Laurent
authors.forename: Guy
authors.initials: G
authors.lastname: Soulas
authors.forename: Françoise
authors.initials: F
authors.lastname: Binet
mesh_terms: D000581:Amidohydrolases / Q000235:genetics; D000818:Animals; D001280:Atrazine / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics; D001673:Biodegradation, Environmental; D004269:DNA, Bacterial / Q000032:analysis; D004275:DNA, Ribosomal / Q000032:analysis; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D017753:Ecosystem; D009835:Oligochaeta / Q000502:physiology*; D011549:Pseudomonas / Q000145:classification / Q000378:metabolism*; D012988:Soil Microbiology
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D021903:DNA, Ribosomal Spacer; D000581:Amidohydrolases; C109894:AtzC protein, Pseudomonas; D001280:Atrazine