title: Endophytic root bacteria associated with the natural vegetation growing at the hydrocarbon-contaminated Bitumount Provincial Historic site.
abstract: The Bitumount Provincial Historic site is the location of 2 of the world's first oil-extracting and -refining operations. Despite hydrocarbon levels ranging from 330 to 24 700 mg·(kg soil)-1, plants have been able to recolonize the site through means of natural revegetation. This study was designed to achieve a better understanding of the plant-root-associated bacterial partnerships occurring within naturally revegetated hydrocarbon-contaminated soils. Root endophytic bacterial communities were characterized from representative plant species throughout the site by both high-throughput sequencing and culturing techniques. Population abundance of rhizosphere and root endosphere bacteria was significantly influenced (p < 0.05) by plant species and sampling location. In general, members of the Actinomycetales, Rhizobiales, Pseudomonadales, Burkholderiales, and Sphingomonadales orders were the most commonly identified orders. Community structure of root-associated bacteria was influenced by both plant species and sampling location. Quantitative real-time polymerase chain reaction was used to determine the potential functional diversity of the root endophytic bacteria. The gene copy numbers of 16S rRNA and 2 hydrocarbon-degrading genes (CYP153 and alkB) were significantly affected (p < 0.05) by the interaction of plant species and sampling location. Our findings suggest that some of the bacterial communities detected are known to exhibit plant growth promotion characteristics.
authors.affiliation: a Department of Soil Science, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N5A8, Canada.
authors.forename: Natalie P
authors.initials: NP
authors.lastname: Blain
authors.affiliation: b Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N 0X2, Canada.
authors.forename: Bobbi L
authors.initials: BL
authors.lastname: Helgason
authors.affiliation: a Department of Soil Science, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N5A8, Canada.
authors.forename: James J
authors.initials: JJ
authors.lastname: Germida
mesh_terms: D001419:Bacteria / Q000235:genetics; D001673:Biodegradation, Environmental; D006838:Hydrocarbons; D063245:Plant Development; D018517:Plant Roots / Q000382:microbiology*; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D058441:Rhizosphere; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis
chemical_list: D006838:Hydrocarbons; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012987:Soil; D012989:Soil Pollutants
keywords: bactéries endophytes racinaires; communautés bactériennes; endophytic root bacteria; hydrocarbures pétroliers; microbial community; petroleum hydrocarbons; reclamation–remediation; réhabilitation–restauration