The crystal proteins from Bacillus thuringiensis subsp thompsoni display asynergistic activity against the codling moth, Cydia pomonella

Crystal proteins from Bacillus thuringiensis subsp. thompsoni strain HnC ar e active against the codling moth, Cydia pomonella, a major pest of orchard s. Inclusion bodies purified from strain HnC displayed an LC50 of 3.34 x 10 (-3) mu g/mu l. HnC-purified crystals were tenfold more active than Cry2Aa and Cry1Aa toxins, and 100-fold more toxic than Cry1Ab. The 34-kDa and 40-k Da proteins contained in HnC inclusion bodies were shown to act synergistic ally. The toxicity of crystal proteins produced by the recombinant B. thuri ngiensis strain BT-OP expressing the full-length native operon was about te nfold higher than that of the 34-kDa protein. When the gene encoding the no n-insecticidal 40-kDa protein, which is not active, was introduced into the recombinant strain producing only the 34-kDa protein, the toxicity was rai sed tenfold and was similar to that of the strain BT-OP.