EXPRESSION OF PARASPORAL CRYSTAL PROTEIN (DELTA-ENDOTOXIN) GENE(S) OFBACILLUS-THURINGIENSIS VAR ISRAELENSIS IN SPOROGENIC AND ASPOROGENIC MUTANT STRAINS OF BACILLUS-CEREUS

The expression of parasporal crystal protein (delta-endotoxin) coding gene(s) of Bacillus thuringiensis var. israelensis and its association , if any, with sporulation was studied in sporogenic Bacillus cereus a nd its asporogenic mutant strains. Five asporogenous mutants of Bacill us cereus blocked at different stages of sporulation, were isolated fr om a streptomycin-resistant strain. The transconjugants isolated from the plasmid transfer experiments between Bacillus thuringiensis var. i sraelensis and streptomycin resistant Bacillus cereus and its asporoge nous mutants, showed larvicidal activity. The crystal protein gene(s) are, therefore, expressed both in sporulating and in non-sporulating m utant strains of Bacillus cereus suggesting that the expression of cry stal protein gene(s), is independent of sporulation specific functions in Bacillus cereus.