Coccolithovirus-Emiliania huxleyi dynamics: an introduction to the coccolithovirocell
Wilson, William H.
Abstract Coccolithoviruses are large double-stranded DNA viruses that infect the globally ubiquitous coccolithophorid Emiliania huxleyi, a marine Haptophyte algae that forms mesoscale blooms. Coccolithoviruses are intrinsically linked to E. huxleyi blooms, providing an essential role in their succession dynamics, often responsible for their demise. The type species of the genus Coccolithovirus is EhV-86 which, along with all other coccolithovirus isolates to date, have been taxonomically assigned to the fringes of the Phycodnaviridae, a family of large DNA viruses that infect algae. Its genome is 407,339 bp and its most notable feature is the presence of a sphingolipid biosynthesis pathway. This and many other features of coccolithovirus genomes provide glimpses to a wider infection strategy that involves unique mechanisms for replication, survival, defence, evolution, dissemination, and communication. A combination of genomic and physiological tools has provided important insights into the infection process of this charismatic virus. The concept of the coccolithovirocell (CLVC) is introduced; the form of infected metabolic life distinct from the uninfected E. huxleyi host. It is argued that the coccolithovirocell is the integral cog that sustains the life of globally omnipresent blooms with Gaian equilibrium.