Synthesis of a Gene Encoding Cry2Aa Delta-endotoxin of Bacillus thuringiensis

The group is responsible for selection, mutation, synthesis and testing of various lepidopteran specific delta-endotoxins of Bacillus thuringiensis. These are tested for their efficacy towards gram podborer and synergetic interactions among various toxins. Site-directed mutagenesis of genes specific to gram podborer is performed to enhance the efficacy of the deltaendotoxins. The gene encoding Cry1Aa delta-endotoxin, which is toxic to gram podborer, was selected for modification and will be available for the present program. Cry2Aa was also found to be highly toxic to gram podborer. The two delta-endotoxins (Cry1Aa and Cry2Aa) belong to different classes of Bt toxins and hence bind to different receptors in the insect midgut epithelium. Expression of a fusion gene encoding these two toxins in transgenic chickpea will provide a viable resistant management strategy.