KARIN HOLMFELDT: Who is killing your bug - Viral stories from aquatic environments

Who is killing your bug - Viral stories from aquatic environments

Karin Holmfeldt

Centre for Ecology and Evolution in Microbial Model Systems (EEMiS), Linnaeus University, Kalmar, Sweden

Viruses on earth have been estimated to be 10 billion more numerous than all the stars in the universe and the majority of these viruses infect microbes. In aquatic environments they commonly outnumber their microbial hosts ten-fold and through host specific infection and lysis they are important for microbial mortality and diversification with cascading ecological effects. By combining isolated virus-bacteria model systems and high-throughput sequencing, the mysteries of viral diversity, functionality, activity, and host interactions have started to be unraveled.

Here I will guide you through an unusually diverse system of twelve different viral genera, including both double- and single-stranded DNA viruses, all infecting the same bacterial species, the aquatic Flavobacterium Cellulophaga baltica. These viruses are not only genetically diverse but also represent a wide variety of host interactions, ranging from generalists to specialists, but also provides information on how viral infection also can be modulated by the host they infect. Further, these viruses may change the host’s functionality, both during infection but also in the resistant microbial population surviving viral infection. Overall, the lessons learned from this model system has largely improved our understanding of the intricate interactions occurring among the smallest biological players in the oceans.