Complete Genome Sequence of Parascardovia denticolens JCM 12538T, Isolated from Human Dental Caries.

Parascardovia denticolens JCM 12538(T) was isolated from human dental caries. Here, we report the complete genome sequence of this organism. This paper is the first report demonstrating the completely sequenced and assembled genome of P. denticolens.

GENOME ANNOUNCEMENT

Parascardovia denticolens JCM 12538T (=DSM 10105T) was originally isolated as Bifidobacterium denticolens from human dental caries (1) and then was renamed P. denticolens (2). P. denticolens is classified under the family Bifidobacteriaceae. This species is isolated from human dental caries and plaque (3, 4) and is also found in microbiota associated with peri-implantitis (5).

We determined the complete genome sequence of P. denticolens JCM 12538T using the whole-genome shotgun strategy using Sanger sequencing (ABI 3730xl sequencers). We constructed small-insert (2-kb) and large-insert (10-kb) genomic DNA libraries and generated 26,880 sequence reads (10.6-fold coverage) for P. denticolens JCM 12538T from both ends of the genomic clones. Data were assembled with the Phred-Phrap-Consed program. Gap closing and resequencing of low-quality regions were conducted by Sanger sequencing to obtain the high-quality finished sequence. The overall accuracy of the finished sequence was estimated to have an error rate of <1 per 10,000 bases (Phrap score of ≥40). An initial set of predicted protein-coding genes was identified using Glimmer 3.0 (6). Genes consisting of <120 base pairs (bp) and those containing overlaps were eliminated. The tRNA genes were predicted by the tRNAscan-SE (7), and the rRNA genes were detected by BLASTn search using known Parascardovia rRNA sequences as queries.

The genome sequence of P. denticolens JCM 12538T consists of a circular chromosome of 1,890,857 bp with no plasmid. The genome size is smaller than those of the Bifidobacterium species, whose genomes range in size from 1.9 to 2.8 Mbp (8). JCM 12538T contained a clustered regularly interspaced short palindromic repeats (CRISPR) (9) region (1,334,669 to 1,340,788), and seven CRISPR-associated genes (PSDT_1094 to PSDT_1100) were encoded upstream of the CRISPR region. The chromosome contains 1,548 predicted protein-coding genes.

P. denticolens JCM 12538T is related to Scardovia inopinata in the phylogenetic tree of the family Bifidobacteriaceae (10). Then, we compared the genome of JCM 12538T with that (1,797,862 bp) of S. inopinata JCM 12537T (GenBank accession no. AP012334). Of the 1,548 protein-coding genes, 1,070 (69%) were conserved in the two strains. The genome information of this species will be useful for further studies of its physiology, taxonomy, clinical aspects, and ecology.

Nucleotide sequence accession number.

The sequence data for the genome have been deposited in DDBJ/GenBank/EMBL under the accession no. AP012333.