Obtaining high pest-resistant transgenic upland cotton cultivars carrying cry1Ac3 gene driven by chimeric OM promoter

Hypocotyl segments from aseptic seedlings of two important cultivars of upland cotton ( Gossypium hirsutum L.) in Northwest China, "Xinluzao-1", "Jinmian-7", "Jinmian-12" and "Jihe-321" were transformed respectively by two efficient plant expression plasmids pBinMoBc and pBinoBc via Agrobacterium turne-faciens. In pBinMoBc, crylAc3 gene, which encodes the Bt toxin, is under the control of chimeric OM promoter. In pBinoBe, it is under control of CaMV 35S promoter. After co-cultivation with Agrobacterium turne-fimpfaciens LBA4404 ( containing pBinMoBc or pBinoBc), kanamycin-resistant selection, somatic embryos were induced and regenerated plants were obtained. Then the regenerated plantlets were grafted to untransformed stocks in greenhouse to produce descendants. The integration of crylAc3 gene and its expression in T-2 generation of transgenic cotton plants were confirmed by Southern hybridization and Western blotting. The analyses of insect bioassay indicated that the transgenic plants of both constructions have significant resistance to the larvae of cotton bollworm ( Heliothis armigera) and that cry 1 Ac3 gene driven by chimeric OM promoter could endue T-2 generation cotton with high pest-resistant ability, implicating that it has a profound application in genetic engineering to breed new pest-resistant cotton varieties.