BACILLUS-THURINGIENSIS CRYSTAL PROTEIN (DELTA-ENDOTOXIN) GENE-EXPRESSION IS INDEPENDENT OF EARLY SPORULATION-SPECIFIC FUNCTIONS

Bacillus thuringiensis produces a parasporal insecticidal crystal prot ein. The correlation between sporulation and crystal protein productio n in Bacillus thuringiensis var. israelensis was studied. The strain w as made resistant against streptomycin (St(R)). Acrystalliferous (Cry- ) cured derivatives and asporogenous acrystalliferous (Spo- Cry-) muta nts blocked at an early stage of sporulation were isolated. Plasmid tr ansfer experiments were performed between St(S) Spo+ Cry+ (streptomyci n sensitive sporogeneous crystalliferous) and St(R) Spo+ Cry- and also between St(S) Spo+ Cry+ and St(R) Spo- Cry- strains. St(R) colonies w ere selected. Insect toxicity was exhibited by the St(R) isolates in b oth the cases. The process of crystal formation is, therefore, indepen dent of early sporulative events.