DISSERTATION RESEARCH: The evolution of symbiotic polydnaviruses in Parapanteles parasitoid wasps

当两个不同的物种有长期和持续的互动时，它们相互影响对方的进化命运。了解这些与其他物种的相互作用是如何随着时间的推移塑造一个有机体的关键，这是理解该有机体如何以及为什么会出现今天的样子的关键，这对于理解自然界的复杂性和多样性至关重要，在试图控制具有经济后果的有机体时非常有用。许多种类的黄蜂将它们的卵注入另一种活着的昆虫的体内，这些活着的昆虫孵化成幼虫，然后幼虫吃掉宿主。小蜂亚科(膜翅目：茧蜂科)的黄蜂使用一种特殊的病毒，多核病毒，以防止它们的宿主毛虫破坏它们的卵和幼虫。小食心蜂是蝴蝶和蛾类毛虫的重要生态天敌和农业天敌，包括许多农业害虫。这项研究将比较来自一小群密切相关的微胃泌素的多聚核糖核酸病毒的基因组。这组微小胃泌素一度是单一物种，攻击1-3种寄主毛虫，但随着时间的推移，进化成约20种，每种攻击不同的毛虫物种。该项目的目标是确定哪些病毒基因变化最大，哪些变化最小，因为这群黄蜂进化成了几个不同的物种，适应了不同的宿主。这将确定哪些病毒基因具有普遍重要的功能，可以使毛虫的免疫防御失效，哪些基因可能具有特定的功能，适合在特定宿主中工作。这将有助于理解多聚核糖核酸病毒如何帮助微胃泌素适应新的宿主毛虫，它们如何能够适应数千种不同的毛虫免疫系统，以及为什么有这么多种类的微胃泌素。这对于理解为什么某些生物群进化成比其他生物群多得多的物种，以及发现控制毛虫物种的新方法尤其重要，其中许多毛虫是重要的农业害虫。干扰宿主免疫的多聚核糖核酸病毒基因被假设为在与宿主免疫适应的进化军备竞赛中快速进化。多聚核糖核酸病毒基因组被整合到微小胃泌素黄蜂的核基因组中。Parapanteles Ashmead是一个小的微胃泌素属，对微胃泌素的寄主利用模式进行了充分的研究。已对连环副金龟的基因组草稿进行了测序和组装，并在其中鉴定了可能的多聚核糖核酸病毒基因。这项研究将对另外20种副斑腿类的基因组进行测序和组装，对它们的多聚核糖核酸病毒基因进行注释，并从系统发育角度研究这些基因是如何进化的，特别是与宿主开关有关的基因。

When two different species have a long-term and consistent interaction they reciprocally influence each other's evolutionary fate. Understanding how these interactions with other species have shaped an organism over time is key to understanding how and why that organism is the way it is today, which is fundamentally important to understanding the complexity and diversity of nature and very useful when trying to control an organism with an economic consequence. Many types of wasps inject their eggs into the body of another living insect, which hatch into larvae that consume the host. Wasps in the subfamily Microgastrinae (Hymenoptera: Braconidae) use a specialized virus, polydnavirus, to prevent their hosts, caterpillars, from destroying their eggs and larvae. Microgastrine wasps are one of the most important ecological and agricultural natural enemies to the caterpillars of butterflies and moths, including many agricultural pests. This research will compare the genomes polydnaviruses from a small group of closely related microgastrines. This group of microgastrines was at one point a single species that attacked 1-3 species of host caterpillars, but evolved over time into about 20 species that each attack different caterpillar species. The goal of this project is to identify which virus genes changed the most and which changed the least as this group of wasps evolved into several different species which have adapted to different hosts. This will identify which virus genes have universally important functions for disabling caterpillars' immune defenses and which genes may have specific functions that are adapted to work in a specific host. This will contribute to understanding how polydnaviruses help microgastrines adapt to new host caterpillars, how they are able to adapt to thousands of different caterpillar immune systems, and why there are so many species of microgastrines. This is especially important for understanding why some groups of organisms evolve into many more species than other groups of organisms, and for discovering new ways to control caterpillar species, many of which are important agricultural pests.Polydnavirus genes that interfere with host immunity are hypothesized to evolve rapidly in an evolutionary arms-race with the host immune adaptations. Polydnavirus genomes are integrated into the microgastrine wasps' nuclear genome. Parapanteles Ashmead is a small microgastrine genus with well-studied microgastrine host use patterns. A draft genome of Parapanteles continua has already been sequenced and assembled and putative polydnavirus genes have been identified within it. This research will sequence and assemble the genomes of 20 more Parapanteles species, annotate their polydnavirus genes, and phylogenetically investigate how these genes have evolved, especially in relation to host-switches.