Division mutants of Bacillus subtilis: isolation and PBS1 transduction of division-specific markers.

A procedure for the isolation of Bacillus subtilis mutants that appear to be defective in septum synthesis has been described. Fourteen mutants isolated with this technique were found to be located at four distinct loci on the B. subtilis chromosome. These have been designated divA, divB, divC, and divD. The four mutants in the divA group synthesize septa; however, they do so with a high frequency of error resulting in minicell production. Mapping data were obtained by scoring cotransduction frequencies using PBS1-transducing lysates. Thus, some of the genes apparently involved in septum synthesis and their order on the genome have been established. The results of a study by electron microscope of some of the mutants is also presented.