Phage-host dynamics
In many environments, the number of bacteria is relatively invariant irrespective of growth rates. This is due to the high predation rates that can rapidly adjust to changes in bacterial productivity. Hence predators exert strong selection on their prey yet very little is known how these processes affect bacterial population diversity and dynamics in the wild. To address this issue, we have recently carried out a highly resolved time series to explore the coupling of predator-prey dynamics on the population level. This has resulted in the largest, fully genome sequenced virus-host interaction network to date with over 300 and 600 sequenced viral and bacterial genomes. One of the most important results of this effort was the discovery of a novel type of virus that resembles double-beta barrel fold of many eukaryotic viruses in its capsid proteins but infects bacteria. Importantly, this viral type matches the dominant morphotype viruses in the ocean whose identity has to date remained enigmatic. In ongoing work, we are exploring how defense against viruses is structured in environmental populations and how this influences the eco-evolutionary dynamics of viruses and their hosts.
Selected references:
Martin-Platero, A., Cleary, B., Kauffman, K.M., Preheim, S.P., McGillicuddy, D.J., Alm, E.J., Polz, M.F. (2018) High resolution time series reveals cohesive but short-lived communities in coastal plankton. Nature Comm. 9(1):266.
Kauffman, K.M., Hussain, F.A., Yang, J., Arevalo, P., Brown, J.M., Chang, W.K., Vaninsberghe, D., Elsherbini, J., Cutler, M.B., Kelly, L., Polz, M.F. (2018) A major lineage of non-tailed dsDNA viruses as unrecognized killers of marine bacteria. Nature 554(7690):118-122.