The ecological and evolutionary consequences of viral plasticity
Juan Bonachela (University of Strathclyde)
Thursday 30th November, 2017 14:00-15:00 311B Mathematics and Statistics Building
(Lunch with the speaker will be at One A The Square, leaving from the school front foyer at 12.45.)
Marine viruses are key top-down regulators of the microbial community and, therefore, influence some of the most important biogeochemical cycles. Due to their parasitic character, viral replication depends deeply on the host physiological state; for example, it is well-documented that the value of key viral traits correlates with host growth, which we refer to here as viral "plasticity". Therefore, viral performance is necessarily affected by dynamic changes in host growth conditions. However, theoretical and experimental studies characterizing host-virus interactions typically neglect such plasticity, which handicaps their ability to describe reliably the short- and long-term dynamics of host-virus systems and, hence, the fate of the microbial community. In this presentation, we will show how a combination of data and theory allowed us to understand the ecological and evolutionary consequences of viral plasticity for the dynamics of the interaction between virus and host. We will first present data-informed functional forms for obligately-lytic bacteriophages that characterize the plastic response of the virus. Including such plasticity in a standard host-virus model, we will discuss how the emergent evolutionary strategies change under different environmental conditions, and the mechanisms underlying such strategies. We will show that plasticity can break the classic trade-off between generation time and offspring number, with the latter driving the evolutionary behavior of the virus. In both stationary and dynamic conditions, plasticity alters dramatically the quantitative and qualitative behavior observed with non-plastic descriptions. Our results highlight the importance of considering this additional level of biological realism to predict reliably key aspects of future oceans such as primary production.