EVALUATION OF SYNERGISTIC INTERACTIONS AMONG THE CRYIVA, CRYIVB, AND CRYIVD TOXIC COMPONENTS OF BACILLUS-THURINGIENSIS SUBSP ISRAELENSIS CRYSTALS

Inclusions consisting of CryIVA, CryIVB, or CryIVD proteins were purif ied from recombinant strains of Bacillus thuringiensis subsp. israelen sis and used in bioassay tests against Aedes aegypti, Anopheles stephe nsi, and Culex pipiens larvae. Two- and three-component mixtures were also tested. Synergy among the three polypeptides was clearly evidence d. In particular, there were synergistic interactions between CryIVA a nd both CryIVB and CryIVD, and simple additive effects between CryIVB and CryIVD. However, other crystal polypeptides presumably contribute to the full toxicity of wild-type B. thuringiensis subsp. israelensis crystals. (C) 1995 Academic Press, Inc.