title: Changes in microbial community composition and function during a polyaromatic hydrocarbon phytoremediation field trial.
abstract: The purpose of this study was to investigate the mechanism by which phytoremediation systems promote hydrocarbon degradation in soil. The composition and degradation capacity of the bulk soil microbial community during the phytoremediation of soil contaminated with aged hydrocarbons was assessed. In the bulk soil, the level of catabolic genes involved in hydrocarbon degradation (ndoB, alkB, and xylE) as well as the mineralization of hexadecane and phenanthrene was higher in planted treatment cells than in treatment cells with no plants. There was no detectable shift in the 16S ribosomal DNA (rDNA) composition of the bulk soil community between treatments, but there were plant-specific and -selective effects on specific catabolic gene prevalence. Tall Fescue (Festuca arundinacea) increased the prevalence of ndoB, alkB, and xylE as well as naphthalene mineralization in rhizosphere soil compared to that in bulk soil. In contrast, Rose Clover (Trifolium hirtum) decreased catabolic gene prevalence and naphthalene mineralization in rhizosphere soil. The results demonstrated that phytoremediation systems increase the catabolic potential of rhizosphere soil by altering the functional composition of the microbial community. This change in composition was not detectable by 16S rDNA but was linked to specific functional genotypes with relevance to petroleum hydrocarbon degradation.
authors.affiliation: Environmental Microbiology Group, Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec. siciliano@sask.usask.ca
authors.forename: Steven D
authors.initials: SD
authors.lastname: Siciliano
authors.forename: James J
authors.initials: JJ
authors.lastname: Germida
authors.forename: Kathy
authors.initials: K
authors.lastname: Banks
authors.forename: Charles W
authors.initials: CW
authors.lastname: Greer
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001673:Biodegradation, Environmental; D004269:DNA, Bacterial / Q000032:analysis; D017753:Ecosystem; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D031751:Festuca / Q000382:microbiology; D006841:Hydrocarbons, Aromatic / Q000378:metabolism*; D008969:Molecular Sequence Data; D018517:Plant Roots / Q000382:microbiology*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism; D029921:Trifolium / Q000382:microbiology
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D006841:Hydrocarbons, Aromatic; D012989:Soil Pollutants