Evolution of Polydnavirus Genes in Microgastrine Braconid Parasitoid Wasps

在攻击和调节毛虫种群的重要寄生蜂中，可能最熟悉和在数量上占主导地位的是属于微胃虫复合体的寄生蜂。这种小蜂复合体包括8个亚科，其中几个亚科已被证明携带损害宿主免疫系统的遗传性多dna病毒，没有一个亚科被证明不携带病毒。由于这些病毒对黄蜂/毛虫的寄生关系至关重要，它们具有相当大的进化、生理和经济意义。基于比较形态学和16S和28S rRNA序列数据的小腹小蜂系统发育分析表明，小腹小蜂形成一个单系谱系，可能可追溯到至少6000万年前。对Cotesia属黄蜂的16S和NADH1 DNA序列数据以及它们携带的病毒的EP1和Crv1基因的系统发育分析的初步结果表明，至少在这一组中，多DNA病毒的系统发育反映了它们的黄蜂携带者的系统发育。本项目将通过获取另外25种微胃虫基因组中的16S、NADH1和CO1基因的DNA序列，并将这些DNA序列与它们携带的病毒的EP1和CrV1基因的系统发育进行比较，更全面地解决这种预期的平行系统发育是否真的存在。这些结果将对使用系统发育学来预测这一大型、经济上重要的黄蜂群的寄主-寄生蜂关系的各个方面具有重要意义。

ABSTRACTPI: WhitfieldProposal: DEB 9873748University of Arkansas Of the parasitoid wasps important in attacking and regulating populations of caterpillars, perhaps the most familiar and numerically dominant are wasps belonging to the microgastroid complex. This complex of braconid wasps comprises eight subfamilies, several of which have already been demonstrated to carry hereditary polydnaviruses which compromise host Immune systems, and none of which have been shown not to carry the viruses. Since these viruses are crucial to the wasp/caterpillar parasitic relationship, they are of considerable evolutionary, physiological and economic interest. Phylogenetic analysis of braconid wasps based on comparative morphology and on 16S and 28S rRNA sequence data indicates that the microgastroids form a monophyletic lineage probably dating back at least 60 million years. Preliminary results of phylogenetic analysis of 16S and NADH1 DNA sequence data, from wasps in the genus Cotesia, and of the genes EP1 and Crv1 from the viruses they carry, suggest that the phylogeny of the polydnaviruses mirrors that of their wasp carriers, at least within this group. This project will more fully address whether this expected parallel phylogeny really exists by obtaining DNA sequences from the 16S, NADH1 and CO1 genes in the genomes of a further 25 species of microgastrines, and comparing the phylogeny obtained from these to that estimated from the EP1 and CrV1 genes of the viruses they carry. The results will have important implications for the use of phylogeny to predict aspects of the host-parasitoid relationship in this large, economically important group of wasps.