This horizontal gene transfer highlights the evolutionary fluidity of the genus. A bacterium does not need to evolve from scratch; it can simply acquire a weapon from a neighbor.
On the beneficial side of the spectrum stands Bacillus subtilis , the model organism for Gram-positive bacteria. It is non-pathogenic and a dominant feature of the rhizosphere (the soil region influenced by root secretions).
The vast majority of Bacillus species are beneficial or neutral: