Bacillus thuringiensis crystal protein (δ-endotoxin) gene expression is independent of early sporulation specific functions.

ABSTRACT

Bacillus thuringiensis produces a parasporal insecticidal crystal protein. The correlation between sporulation and crystal protein production in Bacillus thuringiensis var. israelensis was studied. The strain was made resistant'against streptomycin (StR)- Acrystalliferous (Cry-) cured derivatives and asporogenous acrystalliferous (Spo- Cry-) mutants blocked at an early stage of sporulation were isolated. Plasmid transfer experiments were performed between Sts Spo+ Cry+ (streptomycin sensitive sporogeneous crystalliferous) and StR Spo+ Cry– and also between Sts Spo+ Cry+ and StR Spo– Cry– strains. StR colonies were selected. Insect toxicity was exhibited by the StR isolates in both the cases. The process of crystal formation is, therefore, independent of early sporulative events.