Draft Genome Sequence of Potassium-Dependent Alkaliphilic Bacillus sp. Strain TS-2, Isolated from a Jumping Spider.

The potassium-dependent alkaliphilic Bacillus sp. strain TS-2 was isolated from the mashed extract of a jumping spider, and its draft genome sequence was obtained. Comparative genomic analysis with a previously sequenced sodium-dependent alkaliphilic Bacillus species may reveal potassium-dependent alkaline adaptation mechanisms.

GENOME ANNOUNCEMENT

The typical alkaliphilic Bacillus species (e.g., Bacillus pseudofirmus OF4 and Bacillus halodurans C-125) have a sodium-dependent alkaline adaptation mechanism and show sodium-dependent growth and motility (1, 2). However, some potassium-requiring alkaliphiles have also been reported (3, 4), suggesting the existence of a potassium-dependent alkaline adaptation mechanism. Thus, we have isolated some potassium-dependent alkaliphiles and reported one of their draft genome sequences (5). Here, we report the draft genome sequence of another potassium-dependent alkaliphile, Bacillus sp. strain TS-2. This bacterium was isolated from the mashed extract of a jumping spider and appeared to be most closely related to Bacillus pseudalcaliphilus, based on 16S rRNA gene sequence identity.

The draft genome sequence of Bacillus sp. strain TS-2 was 4,360,646 bp in total length, comprised 58 large contigs (>500 bp), and was obtained using the Roche GS Junior and assembled by GS de novo assembler v. 2.7. Automatic annotation was performed using the Microbial Genome Annotation Pipeline (6), which predicted a total of 4,085 protein-coding genes. The names of products of the predicted protein-coding genes were revised manually. tRNA detection was performed using the ARAGORN software (7), which predicted a total of 73 tRNAs.

Typical alkaliphilic Bacillus species have an atpE gene that encodes an F1Fo-H+-ATPase c subunit, and the amino acid residue that is critical for H+ selectivity under alkaline pH conditions has already been identified (8). The annotation of the draft genome sequence shows that Bacillus sp. strain TS-2 has an atpE gene. The multiple sequence alignment of the ATPase c subunit suggested that the atpE gene of this bacterium encodes an H+-ATPase c subunit that is proposed to function under alkaline pH conditions.

Typical alkaliphilic Bacillus species also have a motPS gene that encodes an Na+-dependent flagellar motor stator protein, and the amino acid residue that is critical for coupling ion selectivity has been identified (2, 4). In the draft genome sequence of Bacillus sp. strain TS-2, a motPS gene was annotated. The multiple sequence alignment of flagellar motor stator proteins suggested that the motPS gene of this bacterium encodes an Na+-dependent flagellar motor stator protein. It would be interesting to analyze the function of this protein in the future.

In the draft genome sequence of Bacillus sp. strain TS-2, two sets of mrp genes, which encode multisubunit secondary cation/proton antiporter-3 family proteins, were annotated. The Mrp complex acts as an Na+/H+ antiporter in typical alkaliphilic Bacillus species and plays a critical role in the sodium-dependent alkaline adaptation mechanism (1, 2). In draft genome sequence analysis of sodium-independent alkaliphilic Microbacterium sp. strain TS-1, three sets of mrp genes were reported (5). Therefore, multiple sets of mrp genes might also support the use of various cations as a coupling ion of H+ influx for alkaline adaptation.

Future genome analysis of other sodium-independent alkaliphiles may reveal common features of novel alkaline adaptation mechanisms.

Nucleotide sequence accession numbers.

The draft genome sequence of Bacillus sp. strain TS-2 was deposited at DDBJ/EMBL/Genbank under the accession number BAWL00000000. The version described in this paper is the first version, BAWL01000000.