Learning to read the oceans genomics of marine phytoplankton

The phytoplankton are key members of marine ecosystems, generating about half of global primary productivity, supporting valuable fisheries and regulating global biogeochemical cycles. Marine phytoplankton are phylogenetically diverse and are comprised of both prokaryotic and eukaryotic species. In the last decade, new insights have been gained into the ecology and evolution of these important organisms through whole genome sequencing projects and more recently, through both transcriptomics and targeted metagenomics approaches. Sequenced genomes of cyanobacteria are generally small, ranging in size from 1.8 to 9 million base pairs (Mbp). Eukaryotic genomes, in general, have a much larger size range and those that have been sequenced range from 12 to 57 Mbp. Whole genome sequencing projects have revealed key features of the evolutionary history of marine phytoplankton, their varied responses to environmental stress, their ability to scavenge and store nutrients and their unique ability to form elaborate cellular coverings. We have begun to learn how to read the 'language' of marine phytoplankton, as written in their DNA. Here, we review the ecological and evolutionary insights gained from whole genome sequencing projects, illustrate how these genomes are yielding information on marine natural products and informing nanotechnology as well as make suggestions for future directions in the field of marine phytoplankton genomics.