Abstract
The rhabdoviruses are a diverse family of RNA viruses that includes important pathogens of humans, animals and plants. We have discovered the sequences of 32 new rhabdoviruses through a combination of our own RNA sequencing of insects and searching public sequence databases. Combining this with previously known sequences we reconstructed the phylogeny of 195 rhabdoviruses producing the most in depth analysis of the family to date. In most cases we know nothing about the biology of the viruses beyond the host they were isolated from, but our dataset provides a powerful way to phylogenetically predict which are vector-borne pathogens and which are specific to vertebrates or arthropods. This allowed us to identify 76 new likely vector-borne vertebrate pathogens among viruses isolated from vertebrates or biting insects. By reconstructing ancestral states, we found that switches between major groups of hosts have occurred rarely during rhabdovirus evolution, with single transitions giving rise to clades of plant pathogens, vertebrate-specific pathogens, and arthropod-borne pathogens of vertebrates. There are also two large clades of viruses that infect insects, including the sigma viruses, which are vertically transmitted. There are also few transitions between aquatic and terrestrial ecosystems. Our data suggest that throughout their evolution rhabdoviruses have occasionally made a long distance host jump, before spreading through related hosts in the same environment.
