Draft Genome Sequence for Desulfovibrio africanus Strain PCS

Desulfovibrio africanus strain PCS is an anaerobic sulfate-reducing bacterium (SRB) isolated from sediment from Paleta Creek, San Diego, CA. Strain PCS is capable of reducing metals such as Fe(III) and Cr(VI), has a cell cycle, and is predicted to produce methylmercury. We present the D. africanus PCS genome sequence.

The genome sequence for strain PCS was generated using Illumina data, as described previously (19). Briefly, CLC Genomics Workbench (version 5.5) was used to trim 100-bp reads from a paired-end library for quality sequence data, and these were then assembled using Velvet (version 1.2.01) (20). The resulting assembly generated 45 DNA contigs for an estimated genome size of 3.9 Mb. The maximum contig size was 609,036 bp, the average contig size was 87,322 bp, and the N 50 was 140,584 bp. The average read depth was approximately 560ϫ the estimated genome size. The draft genome sequence was annotated as previously described (21) and 3,561 candidate protein coding genes were predicted.
The PCS genome had a GϩC content of 61.2%, which is similar to the 61.4% GϩC content reported for strain Walvis Bay (4). Strain PCS shows 95% average nucleotide identity to strain Walvis Bay when the two genome sequences are compared using the JSpecies program (22). Strain PCS contains putative hgcA (PCS_01240) and hgcB (PCS_01242) genes that are~97% and 98% identical, respectively, to their Walvis Bay counterparts at the nucleotide level. In both strains, a gene encoding a predicted radical S-adenosylmethionine (SAM) superfamily or Fe-S oxidoreductase protein is in a 3= position relative to hgcA and 5= relative to hgcB, a genetic organization that differs from those of other MeHg-producing bacteria like D. desulfuricans strain ND132 (16,18). The D. africanus PCS genome sequence will facilitate further studies with this bacterium.
Nucleotide sequence accession numbers. This whole-genome shotgun project has been deposited at DDBJ/EMBL/GenBank under the accession number AOSV00000000. The version described in this paper is the first version, AOSV01000000.

ACKNOWLEDGMENTS
We thank Loren Hauser and Doug Hyatt (ORNL) for examining potential D. africanus hgcA start sites.
The work conducted by ENIGMA-Ecosystems and Networks Integrated with Genes and Molecular Assemblies (http://enigma.lbl.gov), a Scientific Focus Area Program at Lawrence Berkeley National Laboratory, was supported by the Office of Science, Office of Biological and Environmental Research (BER), of the U.S. Department of Energy under contract number DE-AC02-05CH11231. This work was also supported through the BER Mercury Scientific Focus Area led by ORNL. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.