Whole-Genome Sequences of Variants of Bacillus anthracis Sterne and Their Toxin Gene Deletion Mutants.

Here, we report the draft genome sequences of three laboratory variants of Bacillus anthracis Sterne and their double (Δlef Δcya) and triple (Δpag Δlef Δcya) toxin gene deletion derivatives.

GENOME ANNOUNCEMENT

The pathogenicity of Bacillus anthracis, the bacterium that causes anthrax, has been attributed to the presence of two plasmids in its genome, pXO1, which encodes the anthrax toxin genes, and pXO2, which encodes the capsular genes (1). Strains that lack pXO2 (e.g., Sterne) are exempt from select agent regulations and have been used as vaccines (2). Sterne is also the workhorse of laboratory research, and different laboratories have used and propagated Sterne strains over many years; consequently, these strains appear to have accumulated laboratory-specific adaptations. Here, we report the whole-genome draft sequences of three Sterne strains and four toxin gene deletion derivatives.

Libraries were prepared using the Illumina Nextera XT kit and sequenced on an Illumina NextSeq 500 desktop sequencer (V2 mid-output 2 × 151 bp). Adapter sequences were removed with Cutadapt (3) and assembled using SPAdes v3.9 (4). The genome was annotated with the NCBI Prokaryotic Genome Annotation Pipeline v4.2 (5), and reference mapping was done with Bowtie2 v2.0.6 (6).

Accession number(s).

Accession numbers and sequence statistics of the seven genomes are listed in Table 1.

TABLE 1 

Genome sequence details of B. anthracis Sterne variants and their derivatives

Strain	Description	GenBank accession no.	Assembly size (bp)	No. of contigs	No. of CDSsa	Coverage (×)
						Chrb	pXO1c
BA500	Sterne 34F2_FDA	NRIZ00000000	5,358,909	44	5,882	176	1,057
BAP482	BA500 (Δlef Δcya)	NRJA00000000	5,357,360	53	5,889	183	1,014
BAP417	BA500 (Δpag Δlef Δcya)	NRJB00000000	5,354,685	60	5,888	166	953
BA663	Sterne 7702	NRIW00000000	5,362,963	60	5,897	195	1,287
BA721	BA663 (Δlef Δcya)	NRIX00000000	5,347,571	50	5,882	200	1,268
BA781	BA663 (Δpag Δlef Δcya)	NRIY00000000	5,345,676	50	5,877	202	1,244
34F2_Sterne	USAMRIID	NRIV00000000	5,364,310	69	5,905	147	512

CDSs, coding sequences.

NCBI reference sequence NC_005945 (chromosome).

NCBI reference sequence NC_001496 (plasmid).