Exploring Viral Intra-Specific Variation and Behavior Through Host-Range Analysis

Abstract

As the most abundant biological entity in the world’s oceans, marine viruses infect marine bacteria and contribute to major biogeochemical processes through their impacts on microbial metabolism. Despite decades of viral ecology studies, there is still much to learn about these viruses and their behavior. We examined 142 cyanophages isolated from two distinct ecological sites, 77 coastal and 65 upwelling. Phylogenomic analyses clustered these phages into 10 different phylogenetic species, with six of these species with at least three members and members originating from both the coastal and upwelling site. By testing these 142 cyanophages against 15 diverse Synechoccocus strains and analyzing the infectivity patterns associated with these interactions in the first large-scale quantitative host range (qHR), it is possible to explore the concepts of intra vs. inter specific variation and evaluate a potential viral bet hedging behavior. The qHR data has showed that there is more variation of host-range infectivity within species than between species and that viral bet hedging is indeed occurring as a way to minimize population-level extinction through the acceptance of a trade-off in maximal fitness for reduced temporal variance in fitness.