Draft Genome Sequence of Anaeromyxobacter sp. Strain PSR-1, an Arsenate-Respiring Bacterium Isolated from Arsenic-Contaminated Soil.

Here, we report a draft genome sequence of Anaeromyxobacter sp. strain PSR-1, an arsenate-respiring bacterium isolated from arsenic-contaminated soil. It contained three distinct arsenic resistance gene clusters (ars operons), while no respiratory arsenate reductase gene (arr) was identified.

GENOME ANNOUNCEMENT

Anaeromyxobacter dehalogenans is a facultative anaerobic myxobacterium within the Deltaproteobacteria and is able to utilize a wide variety of electron acceptors, including halogenated phenols, nitrate, nitrous oxide, fumarate, oxygen, Fe(III), U(VI), and Se(IV) (1–5). The metabolic versatility of A. dehalogenans makes it a promising candidate for bioremediation, such as the in situ biostimulation of U(VI) immobilization (6). Previously, we isolated a novel arsenate-respiring bacterium, designated strain PSR-1, from arsenic-contaminated soil (7). The strain was phylogenetically closely related to A. dehalogenans 2CP-1T with 16S rRNA gene similarity of 99.7% and utilized not only arsenate but also nitrate, fumarate, oxygen, and Fe(III) as electron acceptors. It is widely accepted that arsenate-respiring bacteria play an important role in arsenic release from anoxic sediments in the form of arsenite (8). To the best of our knowledge, strain PSR-1 is the first Anaeromyxobacter species known to respire arsenate. Therefore, the draft genome sequence of strain PSR-1 may improve our understanding of this genus and its potential role in the biogeochemical cycling of arsenic in the environments.

Strain PSR-1 was grown anaerobically with fumarate as the electron acceptor and DNA was extracted using a DNeasy blood and tissue kit (Qiagen, Hilden, Germany). The draft genome sequence of PSR-1 was prepared using the Roche 454-FLX Titanium, and the sequencing reads were assembled using the Roche GS de novo Assembler (Newbler v. 2.8). After removal of sequences with low sequencing depth, the resulting assembly contains 344 contigs consisting of 4,863,754 bp, with a G+C content of 74.4%. Genome annotation was performed using Prokka 1.9 (9), yielding a total of 4,484 protein-coding genes. Putative gene functions were assigned using public databases, including COG (10), KEGG (11), and Pfam (12).

The genome contains three distinct arsenic resistance gene clusters (ars operons), each of which includes a detoxifying arsenate reductase gene (arsC). One consists of genes for a regulatory protein (arsR), an arsenite efflux pump (arsB), a pump-driving ATPase (arsA), and a chaperone of the pump (arsD) (arsD-arsA-uspA-arsR-arsB-arsC-arsD-ORFs-arsA). The second one consists of similar genes as well as an arsenite methyltransferase gene (arsM) (arsD-arsC-uspA-arsB-arsR-arsM). Respiratory arsenate reductase genes (arrAB) were not identified, despite a unique characteristic of this strain to respire arsenate. The draft genome contains at least 64 genes coding for c-type cytochromes, among which 54 are multiheme cytochromes. A wide variety of genes for type IV pilus assembly proteins (pil genes), flagellar production (fli and flg genes), adventurous motility (agl and agm genes), and chemotaxis proteins (che genes) are identified. Genes for antioxidant proteins, including superoxide dismutase, thiol peroxidase, alkyl hydroperoxide reductase, and rubrerythrin are found, but a catalase-peroxidase gene is absent. A reductive dehalogenase gene is absent. A nearly complete set of genes for the reductive acetyl-CoA pathway was found, except for the formate-tetrahydrofolate ligase gene, but there are no other autotrophic CO2 fixation pathway genes.

Nucleotide sequence accession numbers.

The PSR-1 whole-genome shotgun project has been deposited at DDBJ/EMBL/GenBank under the accession number BAZG00000000. The version described in this paper is the first version, BAZG01000000 (BAZG01000001 to BAZG01000344).