关键词: 棉铃虫, cry2Ah-M, Bt蛋白, 杀虫活性, 烟草

Abstract: Transgenic Bt cotton has gained great ecological and economic benefits after application in research and production for over 20 a, but the resistance risk of cotton boll worm is also increasing gradually. Therefore, exploration of Bt genes by different insecticidal mechanism can not only improve insecticidal efficiency, but also avoid or delay insect resistance effectively. Based on preference of cotton genetic codon, this study  optimized the codon of new Bt gene cry2Ah-like from Bacillus thuringiensis (Bt), constructed plant expression vector, and introduced into tobacco mediated by agro-bacterium. The fact of foreign gene in transgenic tobacco was expressed steadily, RNA was proven and protein level had already been integrated into tobacco genome. The results of biological activity detection showed that after feeding 4 d with transgenic tobacco leaves, the corrected mortality of cotton boll worm can be 8659% and achieving high resistance level. This result further proved that cry2Ah-M gene after codon optimization can express effective and with higher insecticidal activity, and was a new gene for effective prevention of cotton boll worm.

Key words: cotton bollworm, cry2Ah-M, Bt protein, insecticidal activity, tobacco