title: Shifts in root-associated microbial communities of Typha latifolia growing in naphthenic acids and relationship to plant health.
abstract: Naphthenic acids (NAs) are a complex mixture of organic acid compounds released during the extraction of crude oil from oil sands operations. The accumulation of toxic NAs in tailings pond water (TPW) is of significant environmental concern, and phytoremediation using constructed wetlands is one remediation option being assessed. Since root-associated microorganisms are an important factor during phytoremediation of organic compounds, this study investigated the impact of NAs on the microbial communities associated with the macrophyte Typha latifolia (cattail). Denaturing gradient gel electrophoresis revealed that the impact of NAs on microbial communities was niche dependent, with endophytic communities being the most stable and bulk water communities being the least stable. The type of NA used was significant to microbial response, with commercial NAs causing greater adverse changes than TPW NAs. In general, plant beneficial bacteria such as diazotrophs were favoured in cattails grown in TPW NAs, while potentially deleterious bacteria such as denitrifying Dechlorospirillum species increased in commercial NA treatments. These findings suggest that NAs may affect plant health by impacting root-associated microbial communities. A better understanding of these impacts may allow researchers to optimize those microbial communities that support plant health, and thus further optimize wetland treatment systems.
authors.affiliation: Department of Soil Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Lori A
authors.initials: LA
authors.lastname: Phillips
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Armstrong
authors.forename: John V
authors.initials: JV
authors.lastname: Headley
authors.forename: Charles W
authors.initials: CW
authors.lastname: Greer
authors.forename: James J
authors.initials: JJ
authors.lastname: Germida
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D001483:Base Sequence; D002264:Carboxylic Acids / Q000494:pharmacology*; D017931:DNA Primers; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D018744:DNA, Plant / Q000235:genetics / Q000302:isolation & purification; D018527:Hydroponics / Q000379:methods; D008969:Molecular Sequence Data; D010802:Phylogeny; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000382:microbiology*; D012329:RNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D018749:RNA, Plant / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D032401:Typhaceae / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000382:microbiology*
chemical_list: D002264:Carboxylic Acids; D017931:DNA Primers; D004269:DNA, Bacterial; D018744:DNA, Plant; D012329:RNA, Bacterial; D018749:RNA, Plant; D012336:RNA, Ribosomal, 16S; C046170:naphthenic acid