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期 刊 ：植物保护学报 2007年

关键词：中华卵索线虫；昆虫天敌；Bt伴孢晶体蛋白；cry基因型；毒力；

Keywords:Ovomermis sinensis, insect natural enemy, Bt spore-crystal proteins, cry genes type, toxin,

摘 要 ：采用不同浓度的10株Bt伴孢晶体蛋白分别作用于中华卵索线虫受精卵及各期幼虫,探讨该类Bt蛋白对多种农林害虫天敌中华卵索线虫的安全性。结果表明:S1-1、S1-4、S3-2、S3-3、S7-1、S7-6和S8-1等7个菌株同时表达cry1Ac和cry5基因,S1-8、S2-1和HD-1等3个菌株只表达cry1Ac基因。含Cry5蛋白的菌株对线虫卵表现出一定的杀灭毒性,其中S1-4菌株的毒力最强,LD₅₀作用24、48和72h时分别为0.1503、0.1313和0.0182μg/mL。而Bt伴孢晶体蛋白对感染期幼线虫和寄生后期幼线虫无明显致死效应;经Bt处理的感染期幼线虫对棉铃虫的感染率及平均感染强度与对照组无显著性差异(P>0.05), 寄生后期幼线虫能正常蜕皮和交配产卵。将含上述浓度Bt蛋白的棉花叶片喂食已感染线虫的棉铃虫,线虫能够正常发育并从宿主体内脱出。

Abstract:The selective toxicity of 10 Bt spore-crystal proteins to Ovomermis sinensis was studied. The results indicated that 7 of them contained both Cry1Ac and Cry5 proteins (S1-1, S1-4, S3-2, S3-3, S7-1, S7-6 and S8-1), and others only contained Cry1Ac proteins (S1-8, S2-1 and HD-1). We demonstrated that the Bt crystal protein Cry5 from 7 Bt strains were lethal to eggs of O.sinensis. The most effective strain S1-4s LD₅₀ values were 0.1503, 0.1313 and 0.0182μg total protein/mL respectively at 24, 48 and 72h. Infective and post-parasitic juveniles of O.sinensis were unlethal by Bt toxin. Bt toxin had no effect on infective juveniles infective efficiency and average infective intensity in Helicoverpa armigera (P>0.05). Exposure of post-parasitic juveniles to Bt toxins had no effect on their molt and development. Parasitic juveniles of O.sinensis could grow normally in H.armigera which were fed on cottons leaves dealing with low concentrations Bt toxins.

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