title: The effect of anthropogenic arsenic contamination on the earthworm microbiome.
abstract: Earthworms are globally distributed and perform essential roles for soil health and microbial structure. We have investigated the effect of an anthropogenic contamination gradient on the bacterial community of the keystone ecological species Lumbricus rubellus through utilizing 16S rRNA pyrosequencing for the first time to establish the microbiome of the host and surrounding soil. The earthworm-associated microbiome differs from the surrounding environment which appears to be a result of both filtering and stimulation likely linked to the altered environment associated with the gut micro-habitat (neutral pH, anoxia and increased carbon substrates). We identified a core earthworm community comprising Proteobacteria (∼50%) and Actinobacteria (∼30%), with lower abundances of Bacteroidetes (∼6%) and Acidobacteria (∼3%). In addition to the known earthworm symbiont (Verminephrobacter sp.), we identified a potential host-associated Gammaproteobacteria species (Serratia sp.) that was absent from soil yet observed in most earthworms. Although a distinct bacterial community defines these earthworms, clear family- and species-level modification were observed along an arsenic and iron contamination gradient. Several taxa observed in uncontaminated control microbiomes are suppressed by metal/metalloid field exposure, including eradication of the hereto ubiquitously associated Verminephrobacter symbiont, which raises implications to its functional role in the earthworm microbiome.
authors.affiliation: Cardiff School of Biosciences, BIOSI 1, University of Cardiff, P.O. Box 915, Cardiff, Wales, CF10 3TL, UK.
authors.forename: Daniel Antony
authors.initials: DA
authors.lastname: Pass
authors.affiliation: Cardiff School of Biosciences, BIOSI 1, University of Cardiff, P.O. Box 915, Cardiff, Wales, CF10 3TL, UK.
authors.forename: Andrew John
authors.initials: AJ
authors.lastname: Morgan
authors.affiliation: Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford, Oxfordshire, OX10 8BB, UK.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Read
authors.affiliation: Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford, Oxfordshire, OX10 8BB, UK.
authors.forename: Dawn
authors.initials: D
authors.lastname: Field
authors.affiliation: Cardiff School of Biosciences, BIOSI 1, University of Cardiff, P.O. Box 915, Cardiff, Wales, CF10 3TL, UK.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Weightman
authors.affiliation: Cardiff School of Biosciences, BIOSI 1, University of Cardiff, P.O. Box 915, Cardiff, Wales, CF10 3TL, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Kille
mesh_terms: D061271:Acidobacteria / Q000235:genetics / Q000302:isolation & purification; D039903:Actinobacteria / Q000235:genetics / Q000302:isolation & purification; D000818:Animals; D001151:Arsenic / Q000494:pharmacology*; D041963:Bacteroidetes / Q000235:genetics / Q000302:isolation & purification; D042621:Comamonadaceae / Q000235:genetics / Q000302:isolation & purification; D017753:Ecosystem; D020563:Gammaproteobacteria / Q000235:genetics / Q000302:isolation & purification; D064307:Microbiota / Q000235:genetics*; D009835:Oligochaeta / Q000187:drug effects* / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis / Q000494:pharmacology*
chemical_list: D012336:RNA, Ribosomal, 16S; D012987:Soil; D012989:Soil Pollutants; D001151:Arsenic