PRODUCTION OF MULTIPLE DELTA-ENDOTOXINS BY BACILLUS-THURINGIENSIS - DELTA-ENDOTOXINS PRODUCED BY STRAINS OF THE SUBSPECIES GALLERIAE AND WUHANENSIS

A method was developed to assess the number of delta-endotoxins contai ned in Bacillus thuringiensis entomocidal crystals. It utilized proteo lytic conversion of 13O-kDa protoxin into 60- to 65-kDa ''true'' toxin via limited proteolysis with trypsin and separation of stable N-termi nal domains by fast-performance liquid chromatography. Immunodiffusion experiments and N-terminal sequence determination (applied to the maj or component isolated by SDS-PAGE) completed the analysis of the cryst al protein composition. The application of this approach to crystals p roduced by cells of B. thuringiensis subsp. galleriae and wuhanensis a llowed us to identify at least seven and eight different delta-endotox ins, respectively. Among those delta-endotoxins assigned to previously described families, CryIA, CryID, CryIF, and CryIG were found, as wel l as crystal proteins, which possess N-terminal amino acid sequences v ery different from those of all known delta-endotoxins. Possible funct ional consequences of delta-endotoxin multiplicity are discussed.