New types of mutation affecting formation of alkaline phosphatase by Bacillus subtilis in sporulation conditions.

Mutations defining three new loci, sapA, sapB and phoS, were detected by their ability to overcome the phosphatase-negative phenotype of early-blocked asporogenous mutants in sporulation conditions. Synthesis of alkaline phosphatase by Bacillus subtilis is subject to 'vegetative' and 'sporulation' controls. The phoS mutations resulted in constitutive production of alkaline phosphatase and so could be altered in either the 'vegetative' or the 'sporulation' control system. The sapA and sapB mutations only affected alkaline phosphatase formation in sporulation conditions, and were considered to be sporulation specific. They rendered 'sporulation' alkaline phosphatase formation independent of all the spomutations tested, and so independent of the control of the dependent sequences of spo locus expression; as the enzyme was not formed constitutively, it remained subject to some other sporulation control. The sapA and phoS loci were placed between argC4 and metC3 on the genetic map; the sapB locus was located close to purB6. The three loci mapped separately from all known spo loci.