Involvement of SpoVG in hemolysis caused by Bacillus subtilis

Bacillus subtilis is a facultative anaerobic Gram-positive non-pathogenic bacterium that includes members displaying hemolytic activity. To identify the genes responsible for hemolysis, a random mariner-based transposon insertion mutant library of B. subtilis 168 was constructed. More than 20,000 colonies were screened for the hypohemolytic phenotype on blood agar plates. One mutant showed significantly less pronounced hemolytic phenotype than the wild type. DNA sequencing and Southern blot analysis showed this mutant has a single transposable element inserted into the open reading frame (ORF) of the spoVG gene; complementation of the spoVG-disrupted mutant with a wild-type copy restored its hemolytic phenotype. It was therefore concluded that the spoVG gene, which plays a role in regulating asymmetric septation during sporulation in B. subtilis, is involved in hemolysis by B. subtilis.