Isolation and Characterization of a Temperature-sensitive Sporulation Mutant of Bacillus subtilis

Temperature-sensitive sporulation mutants were isolated spontaneously from Bacillus subtilis 168 TT by a sequential transfer method. A representative mutant strain, ts32, was characterized in detail. The mutant grew normally at 30°C and 42°C, but did not sporulate at 42°C. Electron microscopic observation and physiological analysis showed that the mutant was blocked at stage 0-1 of sporulation. Genetic analysis suggested that the mutation was located at the spo0B locus on the B. subtilis chromosome. Temperature-shift experiments clearly showed that the spo0B gene product functions only at the beginning of sporulation.