Molecular ecology of Mamiellales and their viruses in the marine environment
Yau, Sheree; Grimsley, Nigel; Moreau, Hervé
Abstract Mamiellophyceae are a monophyletic class of algae emerging early in the green lineage, within the polyphyletic group of Prasinophytes. Bathycoccus, Micromonas and Ostreococcus are the three most quantitatively important genera in the Mamiellales, an order within the Mamiellophyceae. These organisms are picoeukaryotes (1–3 µm) with a minimal cellular organization. Complete genome sequences for the three genera are available with sizes ranging from 13 to 23 Mb. Ecological studies showed that these three genera are widespread, dominating phytoplankton in some marine environments. Several large DNA prasinoviruses infecting Mamiellales have been described and their genome sequences are available. Prasinovirus abundances in the environment show large spatial and temporal variations and recent metagenomic studies have found that prasinoviruses could be the most abundant large viruses of eukaryotic marine plankton.