title: Comparable dynamics of linuron catabolic genes and IncP-1 plasmids in biopurification systems (BPSs) as a response to linuron spiking.
abstract: On-farm biopurification systems (BPSs) represent an efficient technology for treating pesticide-contaminated wastewater. Biodegradation by genetically adapted bacteria has been suggested to perform a major contribution to the removal of pesticides in BPSs. Recently, several studies pointed to the role of IncP-1 plasmids in the degradation of pesticides in BPSs but this was never linked with catabolic markers. Therefore, a microcosm experiment was conducted in order to examine whether changes in mobile genetic element (MGE) abundances in response to the application of phenylurea herbicide linuron are linked with changes in catabolic genes. Denaturing gradient gel electrophoresis (DGGE) fingerprints of 16S ribosomal RNA gene fragments amplified from total community (TC)-DNA suggested significant shifts in the bacterial community composition. PCR-Southern blot-based detection of genes involved in linuron hydrolysis (libA and hylA) or degradation of its metabolite 3,4-dichloroaniline (dcaQI, dcaQII, and ccdC) in TC-DNA showed that the abundance of the hylA gene was increased faster and stronger in response to linuron application than that of the libA gene, and that the dcaQIIgene was more abundant than the isofunctional gene dcaQI20 and 60 days after linuron addition. Furthermore, a significant increase in the relative abundance of the IncP-1-specific korB gene in response to linuron was recorded. Our data suggest that different bacterial populations bearing isofunctional genes coding for enzymes degrading linuron seemed to be enriched in BPSs in response to linuron and that IncP-1 plasmids might be involved in their dissemination.
authors.affiliation: Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Messeweg 11-12, 38104, Braunschweig, Germany.
authors.forename: Eman H
authors.initials: EH
authors.lastname: Nour
authors.affiliation: Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Messeweg 11-12, 38104, Braunschweig, Germany.|Faculty of Agriculture, Cairo University, Giza, Egypt.
authors.forename: Tarek R
authors.initials: TR
authors.lastname: Elsayed
authors.affiliation: Division of Soil and Water Management, Katholieke Universiteit Leuven, 3001, Leuven, Belgium.
authors.forename: Dirk
authors.initials: D
authors.lastname: Springael
authors.affiliation: Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Messeweg 11-12, 38104, Braunschweig, Germany. kornelia.smalla@julius-kuehn.de.
authors.forename: Kornelia
authors.identifier: http://orcid.org/0000-0001-6980-729X
authors.initials: K
authors.lastname: Smalla
mesh_terms: D000383:Agriculture; D001673:Biodegradation, Environmental; D042621:Comamonadaceae / Q000187:drug effects / Q000235:genetics; D004269:DNA, Bacterial; D058645:Denaturing Gradient Gel Electrophoresis; D006868:Hydrolysis; D020071:Interspersed Repetitive Sequences; D008044:Linuron / Q000378:metabolism* / Q000494:pharmacology; D059013:Microbial Consortia / Q000187:drug effects / Q000235:genetics*; D010575:Pesticides / Q000378:metabolism*; D010957:Plasmids; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S; D012988:Soil Microbiology; D062065:Wastewater
chemical_list: D004269:DNA, Bacterial; D008044:Linuron; D010575:Pesticides; D012336:RNA, Ribosomal, 16S; D062065:Wastewater
keywords: 16S rRNA genes; Degradative genes; PCR hybridization; Plasmids; Total community DNA