DNA sequence of a protein lethal to an endoparasitoid, Cotesia kariyai, encoded in genome of entomopoxvirus amd its spectrum on another endoparasitoid, Meteorus pulchricornis

昆虫痘病毒基因组中编码的对内寄生物 Cotesia kariyai 致死的蛋白质的 DNA 序列及其在另一种内寄生物 Meteorus pulchricornis 上的谱

• 批准号: 14360200
• 负责人: NAKAI Madoka
• 金额: $ 7.81万
• 依托单位: Tokyo University of Agriculture and Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14360200/
• 关键词: entomopoxvirus; parasitoid; Toxic protein; Mythimna separata; Cotesia kariyai; 毒素タンパク

When the gregarious endoparasitoid Cotesia kariyai (Hymenoptera : Braconidae) parasitizes Mythimna separata(Lepidoptera : Noctuidae) larvae that are infected with an entomopoxvirus (MyseEPV), the embryos and larvae of the parasitoid die inside the host before emergence. Previous studies showed that a toxic factor, lethal to Cotesia kariyai, was present in virion-free plasma (VFP) from M.separata larvae infected with MyseEPV. A polypeptide of 28-kDa was purified and designated as Protein Lethal to C.kariyai (PLCK).In this study, we isolated PLCK from MyseEPV infected larvae and determined DNA sequence of a gene encoding PLCK. ORF of pick is 1265bp, and its homologues were found in genomes of Xestia c-nigram (Lepidotera : Noctuidae) granulovirus and Amsacta moori EPV.It has not been known whether PLCK affects parasitoids other than C.kariyai. In this study we examined the effect of PLCK on Meteorus pulchrcornis (Hymenoptera : Braconidae). Like C.kaniyai, M.pulchricornis is a braconid end … More oparasitoid ; however, it is a generalist, parasitizing not only M.separata larvae, whereas C.kariyai is a specialist as only parasitizes M.separata larvae. We observed larval development and survival of these two parasitoids after exposure to PLCK, both in vivo and in vitro. No C.kariyai larvae emerged from M.separata larvae infected with MyseEPV. However, percentages of emergence, pupation and adult eclosion of M.pulchricornis larvae developed in MyseEPV-infected or VFP-injected M.separata larvae were not significantly different from those in non-infected M.separata larvae or that injected with hemolymph from healthy insects. Similarly, M.pulchricornis larvae survived for seven days in IPL-41 medium containing PLCK, but C.karival died within two days in the same medium, showing pathognomonic symptom as the cuticle detachment from the somatic tissues. We also examined immunohistological localization of PLCK within parasitoid larvae developing in medium containing PLCK, to determine whether PLCK attaches to particular tissues in C. kariyai but not in M.pulchricornis. In summaly, PLCK has no effect on the development and survival of M.pulchricornis, but is lethal to C.kariyai. Less

当群居性内寄生蜂Cotesia kariyai（膜翅目：小蜂科）寄生在被虫孔病毒（MyseEPV）感染的Mythimna separata（鳞翅目：夜蛾科）幼虫上时，寄生蜂的胚胎和幼虫在羽化前在宿主体内死亡。先前的研究表明，在感染MyseEPV的分离m.s areata幼虫的无病毒血浆（VFP）中存在一种对kariyai Cotesia致命的毒性因子。纯化了一个28 kda的多肽，并将其命名为“kariyai致死蛋白”（Protein Lethal to C.kariyai， PLCK）。在这项研究中，我们从MyseEPV感染的幼虫中分离出PLCK，并确定了编码PLCK的基因的DNA序列。pick的ORF值为1265bp，其同源物存在于克氏蜱（鳞翅目：夜蛾科）颗粒病毒和毛氏蜱（Amsacta moori） EPV基因组中。目前还不清楚PLCK是否影响除卡里亚疟原虫以外的拟寄生虫。本文研究了PLCK对紫茧蜂（Meteorus pulchrcornis，膜翅目：小蜂科）的作用。与C.kaniyai一样，M.pulchricornis是一种腕足末端。然而，它是一个多面手，不仅寄生于分离蝇幼虫，而卡里亚伊则是一个专门手，只寄生于分离蝇幼虫。我们在体内和体外观察了这两种寄生蜂暴露于PLCK后的幼虫发育和存活情况。染有丝虫病病毒的分离蝇幼虫未孵化出卡里亚氏夜蛾幼虫。与未感染或注射vfp的幼虫及注射健康昆虫血淋巴的幼虫相比，感染或注射myseepv的幼虫羽化率、化蛹率和成虫羽化率无显著差异。同样，M.pulchricornis幼虫在含有PLCK的IPL-41培养基中存活7天，而C.karival幼虫在相同培养基中2天内死亡，表现出体细胞组织角质层脱离的典型症状。我们还检测了PLCK在含有PLCK的培养基中发育的寄生性幼虫中的免疫组织学定位，以确定PLCK是否附着在kariyai的特定组织上，而不附着在M.pulchricornis上。综上所述，PLCK对M.pulchricornis的发育和存活没有影响，但对C.kariyai具有致死性。少