Genome Sequence of Jannaschia aquimarina GSW-M26, a Member of the Roseobacter Clade.

The Gram-negative alphaproteobacterium Jannaschia aquimarina GSW-M26 (DSM 28248) is a member of the Roseobacter clade. The size of the draft genome is 4.1 Mb. Genome analysis revealed the presence of genes encoding a complete gene transfer agent and aerobic anoxygenic photosynthesis. The latter indicated a photoheterotrophic lifestyle.

GENOME ANNOUNCEMENT

The Gram-negative alphaproteobacterium Jannaschia aquimarina GSW-M26 is closely related to Jannaschia seosinensis and Jannaschia helgolandensis (1) and belongs to the Roseobacter clade (2). Strain GSW-M26 (DSM 28248) is the type strain of the species and was isolated from seawater off the southern coast of Korea (1). A study of aerobic bacteriochlorophyll a-producing bacteria in the Baltic Sea showed that members of the genus Jannaschia are of high environmental significance as Jannaschia-related clones constituted up to 25% of all clones with the ability to perform aerobic anoxygenic photosynthesis (3). Despite this importance, only one genome sequence of Jannaschia species is available to date (4). J. aquimarina GSW-M26 (DSM 28248) was derived from the DSMZ (Braunschweig, Germany). The strain was grown in marine broth (MB 2216; BD Difco, Sparks, MD, USA) at 30°C. Chromosomal DNA was isolated with the MasterPure complete DNA purification kit (Epicentre, Madison, WI, USA). Preparation of paired-end sequencing libraries with the Nextera XT library preparation kit and sequencing of the libraries using the Genome Analyzer IIx were performed as described by the manufacturer (Illumina, San Diego, CA, USA). A total of 8,995,698 paired-end reads were derived from sequencing and trimmed using Trimmomatic version 0.32 (5). De novo assembly of all remaining reads with SPAdes version 3.5.0 (6) resulted in 81 contigs and 143.84-fold coverage. The draft genome sequence of J. aquimarina comprises 4.1 Mb and a GC content of 66.4%. Genome annotation was performed with Prokka version 1.10 (7). The draft genome harbored 1 rRNA operon, 51 tRNA genes, and 4,105 protein-encoding genes, of which 3,234 have a predicted function. The presence of a plasmid in J. aquimarina is indicated by genes encoding a plasmid replication system of the RepABC type. This differs from Jannaschia sp. CCS1, which carries a plasmid with a RepA-type plasmid replication system (8). The complete cluster for a gene transfer agent was identified in the J. aquimarina genome. Gene transfer agent–mediated horizontal gene transfer and the corresponding systems have only been found in Alphaproteobacteria but not in all members of the Roseobacter clade (9). It was suggested that these systems represent a potential adaptation mechanism of marine bacteria to maintain their flexibility in dynamic marine environments (10). In addition, a photoheterotrophic lifestyle of J. aquimarina is indicated by a gene cluster typical for aerobic anoxygenic photosynthesis. Genes encoding type I and II carbon monoxide dehydrogenases are present in Jannaschia sp. CCS1 (4), but type I dehydrogenase, which is essential for carbon monoxide oxidation (11), is absent in J. aquimarina. Interestingly, genes similar to sox genes that mediate the oxidation of sulfide or thiosulfate were not observed in the genome of J. aquimarina, although they were identified in the majority of the genomes derived from members of the Roseobacter clade (2). These findings indicate that J. aquimarina GSW-M26 performs a photoheterotrophic but not a chemolithotrophic lifestyle.

Nucleotide sequence accession numbers.

This whole-genome shotgun project has been deposited at DDBJ/EMBL/GenBank under the accession number JYFE00000000. The version described in this paper is version JYFE01000000.