Bacillus subtilis

Overview

Kunst and colleagues reported in 1997 that laboratory strain 168 has a genome of 4,214,810 base pairs with roughly 4,100 protein-coding genes. These figures describe that strain, not every isolate.

The same study noted expanded gene families and at least ten prophage or prophage-like elements, and presented the sequence as a link between molecular genetics and cell physiology.

Sporulation starts when phosphorylated Spo0A triggers asymmetric division into a mother cell and a forespore, which the mother cell then engulfs. Four alternative sigma factors stage gene expression across the two compartments. A comparative-genomics study described a conserved core of about 100 sporulation genes and showed ytaF, ylmC and ylzA are needed for efficient sporulation.

Origins & earliest records

First description and naming history are unverified. How sporulation arose is a phylogenetic hypothesis, not a directly observed event.

Evidence & interpretation

Genome figures rest on the indexed 1997 Nature abstract and indexed author-hosted PDF; publisher full text was not opened. Sporulation details come from an opened 2013 ASM article.

Selected bibliography

Documented works and useful reading. This is not a list of every appearance.

1. 01

   The complete genome sequence of the Gram-positive bacterium Bacillus subtilis

   Kunst et al. · 1997

   Selected bibliography; strain 168 genome paper, Nature 390:249–256.

2. 02

   A Genomic Signature and the Identification of New Sporulation Genes

   Abecasis, Serrano, Alves, Quintais, Pereira-Leal and Henriques · 2013

   Selected bibliography; comparative sporulation-gene study.

Family, evolution & connections

Taxonomic classification

A hierarchy of classified groups, not a chain of direct ancestors.

Source note: Ranked groups in the NCBI Taxonomy snapshot accessed 7 October 2026; these are not identified direct ancestors. NCBI uses Caryophanales and Bacillota; older classifications may use Bacillales and Firmicutes. LPSN confirms the species name and notes that some historical bioindicator strains were reassigned to Bacillus atrophaeus.

1. domainBacteria
2. kingdomBacillati
3. phylumBacillota
4. classBacilli
5. orderCaryophanales
6. familyBacillaceae
7. genusBacillus
8. speciesBacillus subtilis

References

Sources supporting this profile. Linked pages have their own scope and editorial standards.

1. Scientific paper (indexed abstract and author PDF)The complete genome sequence of the Gram-positive bacterium Bacillus subtilisResearch access: 2026-10-06
2. Scientific paperA Genomic Signature and the Identification of New Sporulation GenesResearch access: 2026-10-06
3. Scientific classification referenceNCBI Taxonomy: Bacillus subtilisResearch access: 2026-10-07
4. Scientific classification referenceLPSN: Bacillus subtilisResearch access: 2026-10-07

Image credits

Pink field containing a small stained rod-shaped bacterium near the centre, with several fine flagella visible around it.

CDC identifies the central specimen as Bacillus subtilis; the stain reveals peritrichous flagella. Pink coloration comes from the stained preparation. Original supplied low-resolution image retained (700x460); no magnification or scale inferred. CDC supplies the image freely; use does not imply agency endorsement.