寄生蜂携带的多DNA病毒的起源及其特性  

Origin and Characteristics of Polydnaviruses Carried by Parasitoid Wasps

作　　者：叶熹骞 时敏[1] 陈学新[1] 

机构地区：[1]浙江大学昆虫科学研究所水稻生物学国家重点实验室农业部农业昆虫学重点实验室,杭州310058

出　　处：《中国科学：生命科学》2014年第4期342-350,共9页Scientia Sinica(Vitae)

基　　金：国家重点基础研究发展计划(批准号:2013CB127600)资助项目

摘　　要：病毒在通常意义上都是有害的寄生生物,但是有一类特殊的多DNA病毒(PDV)却成为在数量庞大的寄生蜂的生活史中不可或缺的共生病毒.PDV随着寄生蜂的卵一起被注入到寄主的体内,调控寄主的免疫和发育生理,从而确保幼蜂在寄主体内生存发育.PDV的基因组整合在寄生蜂的基因组内,因此PDV病毒粒子的形成并非在寄主受到侵染的组织内,而是位于寄生蜂卵巢的特定细胞(卵萼细胞)中,其编码的蛋白质几乎没有病毒结构性蛋白,主要的表达产物都用于调控寄主的生理活动.PDV基因编码序列比对分析结果显示,茧蜂病毒(BV)与致病性的裸病毒nudivirus和杆状病毒baculovirus存在一定的亲缘关系,然而这些同源基因已高度分化,具有不同的生物学特性,同时也不能确定这些基因是否还具有原始的功能.在寄生蜂基因组中尚有许多与裸病毒和杆状病毒类似的基因,其中一部分基因能够编码BV病毒粒子的结构蛋白,其表达模式亦与PDV病毒粒子的形成有关.由于PDV使用了与这2种病毒类似的传播途径,才使得寄生蜂的PDV基因转入寄主体内发挥作用,虽然这不能说明PDV属于这2种病毒,至少存在PDV从这2种病毒发展而来的可能性.Viruses are usually small infectious agents and form a pathogenic association with their hosts, but a notable exception to this is polydnaviruses （PDV） which are symbiotic viruses, the obligate mutualists of endoparasitoid wasps that form a giant group in Hymenoptera. PDV virions are injected into caterpillar hosts when parasitoid wasps lay eggs, and induce host immune suppression and developmental arrest to ensure survival of wasp larvae in caterpillar hosts. PDV genome is integrated in a wasp chromosome as a provirus, and therefore PDV virion only replicates in wasp calyx cells which are specialized cells of the wasp ovary, and never express virulence genes in wasp cells. Phylogenetic analyses of viral gene sequences indicate that the members of Bracovirus （BV）, one of two genera of the Polydnaviridae, are closely related to pathogenic nudiviruses and baculoviruses. Moreover, the genome enclosed in the virions encodes almost no viral structural proteins, but interestingly a large set of homologs of nudivirial genes found in the wasp genome encode structural components of the BV virions. Thus BVs do not appear to be nudivirus remnants, but instead employ the same mechanism as nudivirus to delivery virulence genes into caterpillar hosts. Overall, these indicate that nudivirus is probably the ancestor of PDVs.

关 键 词：寄生蜂 多DNA病毒 裸病毒 杆状病毒 寄主调控 

分 类 号：Q939.4[生物学—微生物学]