Bacillus thuringiensis toxins: regulation, activities and structural diversity

To fully realize the potential of Bacillus thuringiensis δ-endotoxins as biopesticides, progress is required in several areas. First, we must increase the yield or efficiency of toxin protein production. Second, we must gain a sufficient understanding of the intoxication process to allow engineering of the toxins for maximum molar activity. Third, we must continue to isolate new strains with novel toxin structures and activities either on known B. thuringiensis targets or on pests thought to be insensitive to B. thuringiensis. And fourth, we must gain a better understanding of the mechanism, and management, of insect resistance to B. thuringiensis toxins. The most notable recent advances in these areas have been improvements in toxin production, resulting from an improved understanding of cry IIIA gene regulation, and a gene discovery effort that has yielded numerous toxins, including an unusual protein that will be the basis for a soil grub killing product.