New Suppressor Mutation surOB of spoOB d spoOF Mutations in

Two extragenic suppressor mutations, surOB20 and swQF1, which restore the sporulation of spoOB or spool: mutants of Bucdlus subtilis to the wild-type level, were obtained. These suppressor mutations were located in the spoOA gene. Their location is close to that of the sop1 mutation, which suppresses s@B, s@E and spoOF mutations. However, Spoo strains bearing the surOB20 mutation differed in several phenotypic characteristics from spo0 mutants bearing the sof-1 suppressor. Nucleotide sequence analysis revealed that the mrOB20 and StltOFl mutations resulted in G1ul4 to Val and Asn, to Lys conversion, respectively, in the spdlA gene. This result indicates that surOB20 is a new suppressor of spoOB and spoOF mutations, whereas sudFl is identical to sof-1.