Department of Biochemistry, Microbiology and Bioinformatics, Université Laval
1030 avenue de la Médecine
418.656.2131 extension 8502
Projet de recherche
Diversity and dynamics of aquatic viruses from the Canadian High Arctic in the context of a changing climate
Arctic ecosystems are increasingly drawing attention from the scientific community due to their Northern location that makes them particularly vulnerable to the effects of global climate change. The rapid pace of change in this region seems likely to result in the loss of unique Arctic taxa and habitats. Despite this increasing interest in Arctic research, the polar viral communities remain poorly understood in spite of the important roles that viruses play in other aquatic ecosystems. Indeed, aquatic viruses modulate the composition and evolution of microbial communities, in addition to modifying the circulation of energy among trophic levels. In polar ecosystems where microbial communities are disproportionately important, viral activity can be a crucial factor in community dynamics. The overarching objective of this project is to characterise the aquatic viral communities in several representative arctic aquatic habitats and to understand their dynamics in this extreme and changing environment. To do so, three lakes have been selected in the region of the northern coast of Ellesmere Island for their unique characteristics: the fresh water lake of Ward Hunt Island (N 85°05, W 74°10), Lake A, a very sharply stratified meromictic lake (N 82°59, W 75°26) and Milne Fiord Lake, the last epishelf lake in the area (N 82°35, W 80°35). The two principle objectives of the study, the assessment of viral diversity and dynamics based on metagenomics and the isolation and characterization of virus-host system, will be studied at these three sites. Eventually, this project could be integrated into efforts to model biological processes in arctic aquatic ecosystems. The metagenomic approach involves collecting water from the chosen sites at different depths, filtering it to separate the viral and cellular fractions and recovering the viral particles. Back in the laboratory, the samples go through nucleic acids extraction, purification and next-generation sequencing. The analysis of viral sequences will allow the portrayal of the lakes’ diversity and allow a comparison between the sites, elucidate the presence of host-virus systems of interest and how these dynamics relate to the physico-chemical parameters of the water column. Focus will be placed on the discovery of auxiliary metabolic genes within the viral metagenome. The isolation of host-virus systems will allow us to test the effects of changes in environmental parameters related to climate change on infection dynamics. This part of the project aims to therefore isolate arctic cyanophage from water samples from the three sites by challenging cyanobacteria isolates that are in the Polar Cyanobacteria Culture Collection at the Université Laval (maintained by the Laboratory of Prof. Warwick F. Vincent). Once isolated, the virus will be purified and amplified in preparation for future experiments. A priority of this work is to understand the role of auxiliary metabolic genes and how their activity varies as a function of environmental conditions during infection.
Trudel, M.V., Vincent, A.T., Attéré, S.A., Labbé, M., Derome, N., Culley, A.I., Charette, S.J., 2016. Diversity of antibiotic-resistance genes in Canadian isolates of Aeromonas salmonicida subsp. salmonicida: dominance of pSN254b and discovery of pAsa8. Scientific Reports, 6: 35617. DOI: 10.1038/srep35617.