Bacteriophage PBSX-induced deletion mutants of Bacillus subtilis 168 constitutive for alkaline phosphatase

Mutants of Bacillus subtilis with deletions extending from the PBSX prophage, and in some cases removing pro(AB) and metC, have been found to be constitutive for vegetatively synthesized alkaline phosphatase. Such deletions were isolated by selecting for heat-resistant derivatives of a strain carrying a xhi-1479 mutation causing heat-inducibility of the defective phage PBSX. These deletions remove the phoS gene, a regulatory gene for alkaline phosphatase; it is concluded that the phoS gene product exerts negative control on alkaline phosphatase synthesis. Deletion mapping, combined with previously published linkage data, indicates a gene order of PBSX-phoS-pro(AB)-metC.