Transgenic Rice Expressing a Fusion Protein of Cry1Ab and Cry9Aa Confers Resistance to a Broad Spectrum of Lepidopteran Pests

摘要

The truncated active Bacillus thuringiensis endotoxin genes, cry1Ab and cry9Aa, were fused to create a fusion gene, cry1Aba€“cry9Aa, encoding a protein of about 146 kDa with Cry1Ab at the N terminus and Cry9Aa at the C terminus. The fusion protein expressed in Escherichia coli is highly active against some major lepidopteran pestsa€”oriental armyworm [Mythimna separata (Walker)], Asian corn borer [Ostrinia furnacalis (Guen??e)], cotton bollworm [Helicoverpa armigera (H??bner)], and tobacco cutworm [Spodoptera litura (Fabricius)]. This fusion gene under the control of the corn (Zea mays L.) polyubiquitin-1 promoter was transformed into rice (Oryza sativa L.) via Agribacterium-mediated transformation. Western blot analysis suggested that the transgenic lines, C19-2 and C19-25, were two high expressers among the 35 transgenic lines obtained. Southern blot analysis revealed that the line C19-2 contains a single copy of the T-DNA, while the C19-25 has three copies. Insecticidal activity assays demonstrated that most of the transgenic rice lines expressing this fusion protein are highly resistant to rice stem borer [Chilo suppressalis (Walker)] and rice leaf folder [Cnaphalocrocis medinalis (Guen??e)]. This study suggested that this fusion gene could be useful for engineering transgenic crops for the control of lepidopteran pests.