Arbovirus population biology: temperature impacts on selection and collective dynamics

节肢动物传播的病毒（虫媒病毒）适应当地条件，最大限度地发挥其潜力， 成为健康威胁。虫媒病毒的适应潜力是由易错复制驱动的， 在每一个宿主体内产生了一个基因多样的竞争病毒基因型库。最重要的一 环境变化的方式是温度在上升。本提案审查了 温度可能影响虫媒病毒进化生物学的方式。 目标1将解决如何综合温度梯度，包括恒定和波动 不同平均值和幅度的温度改变了WNV种群的自然选择， 蚊子和瓶颈的力量。我们的预测是，波动的温度将增加 纯化选择的强度，多样性将在最佳恒温下最大化， 瓶颈将随着温度的升高而变宽。黄病毒感染最常由以下病毒引起： 病毒颗粒的聚集体。目标2将解决这在宿主中发生的程度-和温度- 依赖的方式，使我们以前的工作到一个更生态相关的，现实的背景下。在 目标2的第二阶段，我们将询问这些基因组聚集体是否有助于促进维持 西尼罗河病毒种群的遗传多样性。这一点很重要，因为人口瓶颈可以显著地 影响病毒适应性，个体感染中基因组的聚集可能有助于病毒逃离它们。 我们已经发现，鸟类产生高西尼罗河病毒血症，并高度传染蚊子（乌鸦）， 每个细胞具有比具有较低病毒量的那些（知更鸟）显著更多独特的WNV基因组。目标3将 评估这是否也可能发生在蚊子身上。我们还将评估这种现象在多大程度上 可以允许维持低适应性病毒基因型，同时防止高适应性病毒基因型获得 支配地位申请中提供了支持这些研究可行性的初步数据。 这项工作的重要性在于，它将提供有关变化方式的新颖、全面的数据。 像我们现在所经历的环境条件可能会改变基本的人口 虫媒病毒生物学虫媒病毒对这些条件特别敏感，因为它们必须在 蚊子这本身就很重要。我们的工作也很重要，因为它将提供机械数据， 关于病毒如何在面临选择性和随机遗传减少的情况下保持遗传多样性 多样性最后，我们工作的重要性在于，我们提供了技术和分析工具， 广泛有用，并使我们能够与广泛的调查人员有效合作。拟议 研究在技术上和概念上都是创新的，因为我们可以将联合收割机 在实验室中使用条形码病毒、单细胞方法和其他新的分子工具来构建传输系统。

Arthropod-borne viruses (arboviruses) adapt to local conditions, maximizing their potential to perpetuate and emerge as health threats. The adaptive potential of arboviruses is driven by error-prone replication, which creates a genetically diverse pool of competing virus genotypes within each host. One of the most important ways that the environment is changing is that temperatures are rising. This proposal examines some of the ways that temperature may impact arbovirus evolutionary biology. Aim 1 will address how a comprehensive temperature gradient that includes both constant and fluctuating temperatures with varying means and amplitudes alters natural selection on WNV populations within mosquitoes and the strength of bottlenecks. Our predictions are that fluctuating temperatures will increase the strength of purifying selection, that diversity will be maximized at optimal constant temperatures, and that bottlenecks will become wider as temperature increases. Flaviviruses infections are most frequently initiated by aggregates of virus particles. Aim 2 will address the extent that this occurs in a host- and temperature- dependent manner, bringing our previous work into a more ecologically relevant, realistic context. In the second phase of Aim 2, we will ask whether these genome aggregates can help to facilitate the maintenance of genetic diversity in the WNV population. This is important because population bottlenecks can significantly impact virus fitness, and aggregation of genomes in individual infections may help viruses escape from them. We have found that birds that generate high WNV viremia and are highly infectious to mosquitoes (crows) have significantly more unique WNV genomes per cell than those that have lower viremias (robins). Aim 3 will assess whether this also may occur in mosquitoes. We also will assess the degree to which this phenomenon may allow for the maintenance of low fitness viral genotypes while preventing those of high fitness from gaining dominance. Preliminary data supporting the feasibility of these studies is provided in the application. The significance of this work is that it will provide novel, comprehensive data on the ways that changing environmental conditions such as those that we are now experiencing may alter the fundamental population biology of arboviruses. Arboviruses are uniquely susceptible to these conditions because they must replicate in mosquitoes. This is inherently significant. Our work is also significant because it will provide mechanistic data on how viruses may maintain genetic diversity in the face of both selective and stochastic reductions in genetic diversity. Finally, the significance of our work is that we have provided technical and analytical tools that are broadly useful and have permitted us to collaborate effectively with a wide array of investigators. The proposed studies are technically and conceptually innovative because of the ways that we can combine realistic transmission systems in the lab with barcoded viruses, single cell approaches, and other new molecular tools.