Identifying Mechanisms of Phage-host Interactions

Joy Yang, Massachusetts Institute of Technology

Phage and their bacterial hosts are engaged in an age-old arms race, rapidly acquiring and/or evolving strategies such as adsorption inhibition, restriction-modification and CRISPR-Cas systems, among others. While phage predation is able to impact the ecological differentiation of its host, differentiation of the host strain also can impact the infection strategy. Sampling of ecologically differentiated but closely related hosts can provide insight into the variety of mechanisms by which phage infect their hosts. The Polz lab maintains the Nahant Collection, a rich data set of 277 Vibrio strains that have been challenged by 260 unique phage, all with sequenced genomes. This is the largest phylogenetically resolved host range cross test available to date. Furthermore, these host strains match to well-characterized populations that have been shown to be ecologically differentiated and the phage population captures a diverse range of infection strategies. Mapping out the depths of this rich data set requires carefully designed analysis techniques as well as further experimental exploration. I will first develop methods for systematically identifying genetic pathways that may be involved with phage-host interactions while accounting for population structure. Next, I will focus on a particular mechanism involving tRNAs that the Nahant Collection, on its own, may be underpowered to explore, but in combination with external sources, can be capable of providing valuable insights.

Abstract Author(s): J. Yang, L. Kelly, M. Polz