BLANC - Blanc

Picophytoplankton-virus interactions in a marine ecosystem – PICOVIR

Submission summary

Viruses are extremely numerous, ubiquitous at all depths in oceans, harbour about 200Mt of carbon, and encode a huge reservoir of largely uncharacterised genetic diversity. Eukaryotic picophytoplankton, primordial in the global food chain, are also ubiquitous, very diverse, and their population densities are controlled largely by viruses. We propose to characterise the complete genome sequences of six large DNA viruses (phycodnaviruses) attacking 3 different genera of picophytoplankton (Ostreococcus spp., Bathycoccus spp. and Micromonas spp., 2 viruses for each genus) within the primitive green plant lineage of Mamiellales. All 3 of these genera are present in the 'Golfe du Lion' (Lion Gulf), the North-Western Mediterranean Sea region and its adjoining salt lagoons chosen for this study, and we have recently isolated and cultured viruses of Ostreococcus spp and Bathycoccus spp isolated from this region (unpublished data). Host-virus couples will be chosen first using those host ecotypes for which complete genome sequences are or will shortly be available (5 species in 2 genera, and we have submitted a proposal to 'Genoscope' to analyse the genome of the remaining genus). As phycodnaviruses are 200-400kb in size we expect to characterise about 300 genes per virus and thereby learn much about the mobile diversity of genetic information that is being exchanged and is co-evolving at this primary level of the oceanic ecosystem. In addition, we aim to isolate 8 new clones of each host genus, characterise their growth and rDNA profiles and add them to collections in Roscoff (partner 2) and Banyuls (partner 1). This will permit comparison of host-virus specificities within the region and with external host ecotypes from the well-characterised SOMLIT site (partner 2).

Project coordination

Nigel Grimsley (Organisme de recherche)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.


Help of the ANR 400,000 euros
Beginning and duration of the scientific project: - 36 Months

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