title: Bacterial communities associated with the rhizosphere of pioneer plants (Bahia xylopoda and Viguiera linearis) growing on heavy metals-contaminated soils.
abstract: In this study, the bacterial communities associated with the rhizospheres of pioneer plants Bahia xylopoda and Viguiera linearis were explored. These plants grow on silver mine tailings with high concentration of heavy metals in Zacatecas, Mexico. Metagenomic DNAs from rhizosphere and bulk soil were extracted to perform a denaturing gradient gel electrophoresis analysis (DGGE) and to construct 16S rRNA gene libraries. A moderate bacterial diversity and twelve major phylogenetic groups including Proteobacteria, Acidobacteria, Bacteroidetes, Gemmatimonadetes, Chloroflexi, Firmicutes, Verrucomicrobia, Nitrospirae and Actinobacteria phyla, and divisions TM7, OP10 and OD1 were recognized in the rhizospheres. Only 25.5% from the phylotypes were common in the rhizosphere libraries and the most abundant groups were members of the phyla Acidobacteria and Betaproteobacteria (Thiobacillus spp., Nitrosomonadaceae). The most abundant groups in bulk soil library were Acidobacteria and Actinobacteria, and no common phylotypes were shared with the rhizosphere libraries. Many of the clones detected were related with chemolithotrophic and sulfur-oxidizing bacteria, characteristic of an environment with a high concentration of heavy metal-sulfur complexes, and lacking carbon and organic energy sources.
authors.affiliation: Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, IPN, Prol. de Carpio y Plan de Ayala s/n. Col. Sto. Tomás, Mexico, D.F., Mexico. yendister@gmail.com
authors.forename: Yendi E
authors.initials: YE
authors.lastname: Navarro-Noya
authors.forename: Janet
authors.initials: J
authors.lastname: Jan-Roblero
authors.forename: Maria del Carmen
authors.initials: Mdel C
authors.lastname: González-Chávez
authors.forename: Regina
authors.initials: R
authors.lastname: Hernández-Gama
authors.forename: César
authors.initials: C
authors.lastname: Hernández-Rodríguez
mesh_terms: D019659:Asteraceae / Q000382:microbiology*; D001419:Bacteria / Q000145:classification* / Q000235:genetics; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D054892:Metagenome; D019216:Metals, Heavy / Q000032:analysis*; D008800:Mexico; D008969:Molecular Sequence Data; D010802:Phylogeny; D018517:Plant Roots / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012987:Soil / Q000032:analysis*; D012988:Soil Microbiology
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D019216:Metals, Heavy; D012336:RNA, Ribosomal, 16S; D012987:Soil