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

（深）大陆地下是丰富多样的古生菌和细菌的家园，但人们对感染这些生物的病毒知之甚少。特别令人感兴趣的是占主导地位的初级生产者，因为它们在这些寡营养生态系统中启动食物链，理论上可能是病毒的重要目标。在这个提议中，我们假设Altiarchaeota是一种未被培养的自养地下古菌，出现在全球的热点地区，是新型病毒的常见目标，从而影响碳循环。在初步结果中，我们能够从生物信息学上识别感染Altiarchaeota的假定病毒，并使用direct-geneFISH显示了其中一种病毒在生态系统中的实际感染。在此前提知识的基础上，我们将首先在全球地下位置收集的公共数据集中确定感染Altiarchaeota的移动遗传元素。这些元素将包括病毒，我们将在德国的主要研究地点详细研究其中一种病毒的微多样性。在我们的第二个目标中，我们将使用直接基因鱼、超分辨率显微镜和拉曼显微镜的组合来可视化和计算选定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病毒的结构。这些方法包括直接基因fish介导的原子力显微镜和透射电子显微镜，以及用预测和异源表达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个未经培养的病毒-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。这一建议的结果将揭示深层地下病毒的多样性和功能，这些病毒感染自噬古细菌，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.