Expression of two insect-resistant genes crylA ( b&c )/GNA in transgenic tobacco plants results in added protection against both cotton bollworm and aphids

The synthesized Bacillus thuringiensis insecticidal protein gene crylA(b&c) and the synthesized gene GNA, (the mannose specific lectin from snowdrop ( Galanthus nivalis)), tumefaciens have been inserted into plant expression vector pGW4BAI. Leave stripes of Nico-tiana tabacum var. K326 have been transformed with Agrobacterium tumefaciens strain LBA4404 harboring the plant expression vector. 28 kanamycin resistant tobacco plants have been obtained. PCR and Southern blot analyses show that the foreign crylA and GNA genes have been inserted into the genome of transformed tobacco plants. Haemagglutination assays show that GNA has a functional activity. Leaf disc bioassays against cotton bollworm ( H. armigera) show that the transgenic tobacco plants have a high insecticidal activity. The inhibition of aphid population in leaf disc bioassays against Myzus persicae shows that the fecundity of aphid on transgenic plants is lower than that on untransformed plants; the aphid population on the transgenic tobacco plants is 25%-70% that on untransformed tobacco plants. ELISA analysis of CrylA protein in tobcco leaves provides similar data to bioassay results. Through the two bioassays against H. armigera and M. persicae, several transgenic tobacco plants showing high insect-resistant activities to both pests have been obtained.