Genetic analysis of autolysin-deficient and flagellaless mutants of Bacillus subtilis.

Three mutants with an autolysin-deficient and flagellaless phenotype (lyt) were genetically analyzed and compared with three thermosensitive flagellaless mutants. In view of the near indistinguishability of their phenotypes, all six mutations were assigned to fla loci. They were distributed into four linkage groups, designated flaA through flaD. flaA and flaB map between pyrD and thyA, flaD maps between aroD and lys, and, in agreement with a previous report, flaC maps near hisA. A locus associated with hypermotility, ifm-3, maps near the latter marker. Introduction of ifm-3 into lyt-1- and flaA4-containing strains led to partial suppression of the nonmotile phenotype. We discuss the possibility that the cellular concentration of autolysins is regulated by the expression of fla genes. Discrepancies with respect to previous mapping of flaA and flaB are accounted for.