Host-virus dynamics of a novel algal virus system

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Algae are the engines of aquatic ecosystems that convert inorganic matter into organic and fuel aquatic food webs. Their growth influences the productivity of aquatic environments, and also environmental quality by either supporting or impeding beneficial human use; e.g., by sustaining fisheries, or forming nuisance blooms. A couple of decades ago, scientists discovered that viruses infecting algae are present in nearly all aquatic environments, and that most of these pathogens are species-specific and cause the lysis, or death, of their hosts. These discoveries raised many questions about the influence of viruses on aquatic primary production and their role in algal ecology and evolution. Research since has taught us much about the importance of virus in aquatic ecosystems, but many fundamental questions remain unanswered.***My work concerns the interactions of viruses and algae with the goal of enhancing our ability to predict the response of aquatic ecosystems to environmental change. Evidence that viruses and their hosts interact in a dynamic manner, each influencing the growth and evolution of the other is accumulating. However, these interactions seem complex and are rarely predictable. Some viruses appear to drive their host populations through boom and bust cycles while others stably coexist with their hosts, and the mechanisms for these different interactions are unknown. Hence, my future research will explore the interactions of algae and viruses asking the questions: do algal viruses regulate their host populations and vice versa, and does the pattern of virus-host interactions (boom/bust versus coexistence) change over time and is it influenced by environmental conditions? To address these questions I will focus on a novel algal virus recently isolated from Lake Ontario by my research group. First, I will create a monitoring program and use molecular tools to determine if fluctuations in the abundances of the virus and its host can be perceived synchronous or asynchronous depending on the temporal scale of sampling or our ability to discriminate different strains of these microorganisms. Second, I will study the influence of host growth status on the virus to determine if virus propagation depends on environmental conditions. Finally, I will monitor gene expression throughout the course of infections to determine if and when virus genes are differentially expressed under differing environmental conditions.***These projects will provide training opportunities for highly sought research techniques ranging from environmental monitoring to molecular biology. My research will inform models of aquatic ecosystems by enhancing our understanding of the role of viruses in primary production, and will teach us if and how the environment influences virus activity. This work will also contribute to understanding of virus ecology and therefore, the epidemiology of viral pathogens.******