title: Evidence for taxonomic and functional drift of an atrazine-degrading culture in response to high atrazine input.
abstract: We evaluated the effects of variations in atrazine input on the evolution of a bacterial culture adapted to a low atrazine concentration. This initial culture (M3-K) was subjected to weekly subculturing in the presence of a high concentration of atrazine as the only N source (100 mg l(-1)). After four subculturing, M3-K evolved to a new bacterial culture (M3) which exhibited a significant increase in the extent of atrazine mineralization in comparison with the initial culture. Molecular analyses of M3-K and M3 cultures by cloning, restriction analysis, and sequencing of the 16S rRNA genes revealed significant differences in culture structure and composition. M3-K culture comprised mainly Actinobacteria (40%), β-Proteobacteria (26%), and Bacteroidetes (16%). After exposure to a high atrazine concentration, the dominance of Actinobacteria decreased (14%), Bacteroidetes increased (27%), and β-Proteobacteria were replaced by γ-Proteobacteria (32%). Quantitative PCR revealed that the abundance of atzB and atzC genes relative to total bacteria decreased by a factor of 3-4 following the increase in atrazine concentration, while the relative abundance of trzD increased significantly (≈400 times). Presented study shows that variations in atrazine input drive both functional and compositional shifts in the atrazine-degrading bacterial culture.
authors.affiliation: Division for Marine and Environmental Research, Rudjer Bošković Institute, Zagreb, Croatia. nikolina.udikovic.kolic@irb.hr
authors.forename: Nikolina
authors.initials: N
authors.lastname: Udiković-Kolić
authors.forename: Marion
authors.initials: M
authors.lastname: Devers-Lamrani
authors.forename: Ines
authors.initials: I
authors.lastname: Petrić
authors.forename: Dubravka
authors.initials: D
authors.lastname: Hršak
authors.forename: Fabrice
authors.initials: F
authors.lastname: Martin-Laurent
mesh_terms: D001280:Atrazine / Q000378:metabolism*; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001673:Biodegradation, Environmental; D008969:Molecular Sequence Data; D010575:Pesticides / Q000378:metabolism*; D010802:Phylogeny
chemical_list: D010575:Pesticides; D001280:Atrazine