摘 要 ：嗜线虫致病杆菌北京变种Xenorhabdus var. pekingensis CB6菌株是本研究室自主分离的新菌株,其代谢物对棉铃虫具有很强的拒食和抑制生长活性。为了进一步明确代谢物中杀虫蛋白的生物活性,作者用饲料染毒法和叶碟法测定了杀虫蛋白对棉铃虫不同龄期幼虫取食和生长发育的影响。结果表明,杀虫蛋白对棉铃虫幼虫有很强的抑制生长作用,用64μg/g含杀虫蛋白饲料饲喂初孵、1、2和3龄幼虫5天的生长抑制率分别达95.37%、92.73%、87.15%和88.64%,并明显延长幼虫发育历期,影响幼虫的化蛹及蛹的羽化。杀虫蛋白对5龄棉铃虫幼虫拒食效果明显,幼虫饲喂经1.6mg/mL杀虫蛋白处理的叶片24h, 选择性拒食率和非选择性拒食率分别为76.22%和85.42%。当蛋白浓度为0.32mg/mL时, 24h选择性拒食和非选择性拒食率分别为68.39%和74.75%。
Abstract:Xenorhabdus nematophila var. pekingensis is a new strain separated and identified by authors. Its metabolite could inhibit insect larva feeding and growth. In order to illuminate the insecticidal activity of protein separated from the metabolite, the antifeeding and grow inhibition of the insecticidal protein to Helicoverpa armigera larvae were studied. The growth inhibitions were 95.37%, 92.73%, 87.15% and 88.64% while neonate and 1-3rd instar larvae were fed with artificial diet mixed with 64μg/g (v/w) protein. The insecticidal protein obviously decreased larva weight, prolonged larva stage and decreased the rate of pupation and emergence. When 5th instar larvae of H.armigera were fed with leaf dipped in 1.60mg/mL protein, the antifeeding was 76.22% and 85.42% respectively for choice and no-choice tests in 24h. The antifeeding was 68.39% and 74.75% while the insecticidal protein was 0.32mg/mL.