NOVAC – Novel viruses of terrestrial subsurface archaea impacting global carbon cycling

(深层)大陆地下蕴藏着丰富多样的古生菌和细菌，但人们对感染这些微生物的病毒知之甚少。尤其令人感兴趣的是占主导地位的初级生产者，因为他们启动了这些少营养生态系统中的食物链，理论上可能是病毒的重要目标。在这项提议中，我们假设Altiarocota是一组未培养的自养地下古细菌，出现在全球的热点地区，经常成为新病毒的目标，从而影响碳循环。在初步结果中，我们能够通过生物信息识别感染阿尔蒂考古塔的假定病毒，并使用直接基因FISH显示这些病毒之一在生态系统中的实际感染。在这一先决知识的基础上，我们将首先在从全球地下地点收集的公共数据集中识别感染阿尔蒂考古动物的移动遗传元素。这些成分将包括病毒，其中一种病毒将在我们在德国的主要研究地点就其微多样性进行详细调查。在我们的第二个目标中，我们将使用直接基因FISH、超分辨率显微镜和拉曼显微镜的组合来可视化和计算所选病毒在生态系统中的感染率。在第三个目标中，我们计划使用三种独立的显微镜方法来鉴定预测的病毒的结构。这些方法包括直接基因FISH介导的原子力显微显微镜和透射电子显微镜，以及用预测的和异源表达的蛋白产生的抗体对病毒蛋白进行免疫金标记。这些方法最终将产生一种未培养的病毒-宿主关系的综合数据集，以揭示病毒在实际生态系统中的不同感染阶段。这一提议的结果将为深层地下病毒的多样性和功能提供新的线索，这些病毒感染自养古菌，从而改变这些环境中的碳循环。

The (deep) continental subsurface is home to a great abundance and diversity of archaea and bacteria, yet little is known about the viruses that infect these organisms. Of particular interest are dominant primary producers as they jump-start the food chain in these oligotrophic ecosystems and could in theory be an important target for viruses. In this proposal we hypothesize that Altiarchaeota, an uncultivated group of autotrophic subsurface archaea that occur in hot spots across the globe, are frequent targets of novel viruses that consequently impact carbon cycling. In preliminary results, we were able to bioinformatically identify putative viruses infecting Altiarchaeota and showed the actual infection of one of these viruses in the ecosystem using direct-geneFISH. Building on this prerequisite knowledge, we will first identify mobile genetic elements that infect Altiarchaeota, in public datasets collected from subsurface locations across the globe. These elements will include viruses, one of which will be investigated in detail regarding its microdiversity in our main study site in Germany. In our second goal, we will visualize and calculate the infection rates of the selected virus in the ecosystem using a combination of direct-geneFISH, superresolution microscopy and Raman microscopy. In the third goal, we plan to identify the structure of the predicted virus using three independent microscopy approaches. These approaches include direct-geneFISH-mediated atomic force microsopy and transmission electron microscopy as well as immunogold labeling of viral proteins with antibodies generated from predicted and heterologously expressed proteins. These approaches will ultimately result in a comprehensive dataset of one uncultivated virus-host relationship in order to unravel the different infection stages of a virus in the actual ecosystem. The results of this proposal will shed new light on the diversity and function of deep subsurface viruses that infect autotropic archaea and thus alter carbon cycling in these environments.