Viral Tagging: a high-throughput approach to explore virus-host interactions

Viruses kill hosts, horizontally transfer genes, and alter global biogeochemistry through manipulating host metabolism. Yet, linking a virus to its host remains problematic. Here we introduce ‘viral tagging’ which experimentally identifies viruses from a laboratory mixture or wild community that infect particular cultured host cells. Viral tagging is sensitive, specific and high-throughput. Application to model systems revealed fundamentally different strategies for slow- and fast-growing hosts. Viral tagging a cyanobacterium using wild ocean viruses revealed new insights into the diversity of viruses infecting this host, the “host” genes they carry, and the first complete large virus genome (173kb, T4-like myovirus) assembled from the wild. Experimentally linking wild viruses to their hosts represents a powerful tool for exploring the virus-host interactions that govern the Earth System.