肠道菌对苏云金芽胞杆菌杀虫活性的研究

苏云金芽胞杆菌(Bacillus thuringiensis,Bt)在生长发育过程中伴随芽胞的形成高效表达对昆虫具有特异毒性的杀虫晶体蛋白,从而被广泛应用于害虫防治上。有关Bt的杀虫机制,近年来有学者提出了肠道菌模型,认为肠道菌在Bt发挥杀虫活性中是必须的,也有人提出相反的观点。以棉铃虫作为供试昆虫,利用Cry1Ac10晶体蛋白研究了棉铃虫肠道菌在Bt杀虫过程中所发挥的功能。结果发现,在棉铃虫中肠道菌并非Bt杀虫所必需,并且在肠道菌存在的情况下,Bt杀虫活性反而明显降低,通过肠道菌回接试验发现5号肠道菌对棉铃虫的保护作用最为明显。

Effects of Gut Bacteria to the Insecticidal Activity of Bacillus thuringiensis Toward Helicoverpa armigera

Bacillus thuringiensis has been widely used in pest control as the formation of the highly expressed peculiar toxic insecticidal crystal proteins accompanying with its growth.As for the insecticidal mechanism of B.thuringensis,recently some researchers put forward the gut bacteria model,believe that these symbiotic bacteria are necessary for insecticidal activity of B.thuringiensis,but also some others debate with it.In this paper,we used Helicoverpa armigera as experimental insect,discussed whether symbiotic gut bacteria of H.armigera play a significant role in insecticidal activity of Cry1Ac10 crystal protein toward the host.We found in H.armigera,gut bacteria are not necessary for insecticidal activity,instead these bacteria protected H.armigera obviously and No.5 bacteria reduced the sensitivity of insecticidal crystal protein toward H.armigera most.