A survey of the bacterial root endophytes associated with the natural vegetation at the Bitumount Provincial Historic site, Alberta, Canada.
Blain, Natalie Pierrette 1990-
The Bitumount Provincial Historic site is the location of two of the world’s first oil extracting and refining operations. Bitumount, located in the Athabasca oil sands of Alberta, is thought to be impacted by hydrocarbons through both natural and human activity. Plants have been able to recolonize the site in spite of varying hydrocarbon levels, through means of natural revegetation. Due to the apparent resilience of these plant species, Bitumount offers a unique opportunity to study the root-associated bacterial communities. This study was designed to achieve a better understanding of the root-associated partnerships occurring within naturally revegetated hydrocarbon contaminated soils. Plant and soil samples were collected in June 2014. Six representative plant species were identified and collected based on abundance on site, including smooth brome (Bromus inermis, SB), horsetail species (Equisetum spp., HT), slender wheatgrass (Agropyron trachycaulum, SW), Kentucky bluegrass (Poa pratensis, KB), an unspecified member of the pea family (Fabaceae, PF), and wild strawberry (Fragaria virginiana, WS). Population abundance of rhizosphere and root endosphere bacteria was significantly influenced (p<0.05) by plant species and sampling location. The vegetation was found to support diverse root endophytic communities despite hydrocarbon contamination. Culture dependent techniques were able to identify some of the more abundant bacteria characterized by high-throughput sequencing. In general, members of the Actinomycetales, Rhizobiales, Pseudomonadales, Burkholderiales, and Sphingomonadales orders were the most commonly identified via both techniques. Community structure of root-associated bacteria was found to be 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 two hydrocarbon degrading genes (CYP153 and alkB; both of the alkane hydroxylase family) were quantified. The gene copy abundance of 16S rRNA, CYP153, and alkB was significantly affected by the interaction of plant species and sampling location. The increased colonization of hydrocarbon degrading bacteria within grass species emphasizes their ability to be used for reclamation efforts. Overall, it was found that the endosphere was able to support diverse bacterial communities with known plant growth promoting abilities. In addition, the diversity and abundance of the endophytic bacteria was influenced by many different factors instead of one sole dominant one. The findings of this study provide insight into the root-associated bacterial communities occurring within natural revegetated soils.
DegreeMaster of Science (M.Sc.)
DepartmentAgricultural and Bioresource Engineering
SupervisorHelgason, Bobbi; Germida, Jim
CommitteeVan Rees, Ken; Walley, Fran; Yost, Christopher
Copyright DateSeptember 2016
Bitumount, Reclamation/ Remediation, Endophytic root bacteria, Petroleum hydrocarbon, Plant growth promotion, Microbial community assessment