title: Bacteria associated with arbuscular mycorrhizal fungi within roots of plants growing in a soil highly contaminated with aliphatic and aromatic petroleum hydrocarbons.
abstract: Arbuscular mycorrhizal fungi (AMF) belong to phylum Glomeromycota, an early divergent fungal lineage forming symbiosis with plant roots. Many reports have documented that bacteria are intimately associated with AMF mycelia in the soil. However, the role of these bacteria remains unclear and their diversity within intraradical AMF structures has yet to be explored. We aim to assess the bacterial communities associated within intraradical propagules (vesicles and intraradical spores) harvested from roots of plant growing in the sediments of an extremely petroleum hydrocarbon-polluted basin. Solidago rugosa roots were sampled, surface-sterilized, and microdissected. Eleven propagules were randomly collected and individually subjected to whole-genome amplification, followed by PCRs, cloning, and sequencing targeting fungal and bacterial rDNA. Ribotyping of the 11 propagules showed that at least five different AMF OTUs could be present in S. rugosa roots, while 16S rRNA ribotyping of six of the 11 different propagules showed a surprisingly high bacterial richness associated with the AMF within plant roots. Most dominant bacterial OTUs belonged to Sphingomonas sp., Pseudomonas sp., Massilia sp., and Methylobacterium sp. This study provides the first evidence of the bacterial diversity associated with AMF propagules within the roots of plants growing in extremely petroleum hydrocarbon-polluted conditions.
authors.affiliation: Institut de recherche en biologie végétale, Département de sciences biologiques, Université de Montréal 4101 Sherbrooke est, Montréal, QC, Canada.
authors.forename: Bachir
authors.initials: B
authors.lastname: Iffis
authors.forename: Marc
authors.initials: M
authors.lastname: St-Arnaud
authors.forename: Mohamed
authors.initials: M
authors.lastname: Hijri
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000254:growth & development*; D058448:Biota; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D006838:Hydrocarbons; D008969:Molecular Sequence Data; D038821:Mycorrhizae / Q000254:growth & development*; D010578:Petroleum; D010802:Phylogeny; D018517:Plant Roots / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D021521:Ribotyping; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D012989:Soil Pollutants; D036624:Solidago / Q000254:growth & development / Q000382:microbiology
chemical_list: D004269:DNA, Bacterial; D004271:DNA, Fungal; D004275:DNA, Ribosomal; D006838:Hydrocarbons; D010578:Petroleum; D012336:RNA, Ribosomal, 16S; D012337:RNA, Ribosomal, 18S; D012989:Soil Pollutants
keywords: 16S and 18S rRNA genes; Solidago rugosa; arbuscular mycorrhizal fungi; bacteria; petroleum hydrocarbons