Host-virus dynamics of a novel algal virus system

藻类是水生生态系统的引擎，将无机物转化为有机物，并为水生食物网提供燃料。它们的生长通过支持或阻碍人类的有益利用而影响水生环境的生产力和环境质量；例如，通过维持渔业，或形成有害的水华。几十年前，科学家们发现，感染藻类的病毒几乎存在于所有的水生环境中，而且这些病原体中的大多数都是物种特异性的，它们会导致宿主的裂解或死亡。这些发现提出了许多关于病毒对水生初级生产的影响及其在藻类生态和进化中的作用的问题。此后的研究让我们了解了病毒在水生生态系统中的重要性，但许多基本问题仍未得到解答。我的工作涉及病毒和藻类的相互作用，目的是提高我们预测水生生态系统对环境变化的反应的能力。越来越多的证据表明，病毒及其宿主以一种动态的方式相互作用，相互影响对方的生长和进化。然而，这些相互作用似乎很复杂，而且很难预测。有些病毒似乎驱使宿主群体经历繁荣和萧条的周期，而另一些病毒则与宿主稳定共存，而这些不同相互作用的机制尚不清楚。因此，我未来的研究将探索藻类和病毒的相互作用，并提出以下问题：藻类病毒是否调节宿主种群，反之亦然，病毒与宿主相互作用的模式（繁荣/萧条与共存）是否随时间而变化，是否受到环境条件的影响？为了解决这些问题，我将把重点放在我的研究小组最近从安大略湖分离出的一种新型藻类病毒上。首先，我将创建一个监测程序并使用分子工具来确定病毒及其宿主的丰度波动是同步的还是异步的取决于采样的时间尺度或我们区分这些微生物不同菌株的能力。其次，我将研究宿主生长状态对病毒的影响，以确定病毒的传播是否依赖于环境条件。最后，我将在整个感染过程中监测基因表达，以确定病毒基因在不同环境条件下是否以及何时差异表达。这些项目将为从环境监测到分子生物学等广受欢迎的研究技术提供培训机会。我的研究将通过加强我们对病毒在初级生产中的作用的理解，为水生生态系统模型提供信息，并将告诉我们环境是否以及如何影响病毒活动。这项工作也将有助于了解病毒生态学，从而有助于了解病毒病原体的流行病学。******

Algae are the engines of aquatic ecosystems that convert inorganic matter into organic and fuel aquatic food webs. Their growth influences the productivity of aquatic environments, and also environmental quality by either supporting or impeding beneficial human use; e.g., by sustaining fisheries, or forming nuisance blooms. A couple of decades ago, scientists discovered that viruses infecting algae are present in nearly all aquatic environments, and that most of these pathogens are species-specific and cause the lysis, or death, of their hosts. These discoveries raised many questions about the influence of viruses on aquatic primary production and their role in algal ecology and evolution. Research since has taught us much about the importance of virus in aquatic ecosystems, but many fundamental questions remain unanswered.***My work concerns the interactions of viruses and algae with the goal of enhancing our ability to predict the response of aquatic ecosystems to environmental change. Evidence that viruses and their hosts interact in a dynamic manner, each influencing the growth and evolution of the other is accumulating. However, these interactions seem complex and are rarely predictable. Some viruses appear to drive their host populations through boom and bust cycles while others stably coexist with their hosts, and the mechanisms for these different interactions are unknown. Hence, my future research will explore the interactions of algae and viruses asking the questions: do algal viruses regulate their host populations and vice versa, and does the pattern of virus-host interactions (boom/bust versus coexistence) change over time and is it influenced by environmental conditions? To address these questions I will focus on a novel algal virus recently isolated from Lake Ontario by my research group. First, I will create a monitoring program and use molecular tools to determine if fluctuations in the abundances of the virus and its host can be perceived synchronous or asynchronous depending on the temporal scale of sampling or our ability to discriminate different strains of these microorganisms. Second, I will study the influence of host growth status on the virus to determine if virus propagation depends on environmental conditions. Finally, I will monitor gene expression throughout the course of infections to determine if and when virus genes are differentially expressed under differing environmental conditions.***These projects will provide training opportunities for highly sought research techniques ranging from environmental monitoring to molecular biology. My research will inform models of aquatic ecosystems by enhancing our understanding of the role of viruses in primary production, and will teach us if and how the environment influences virus activity. This work will also contribute to understanding of virus ecology and therefore, the epidemiology of viral pathogens.******