title: Intragenus competition between coccolithoviruses: an insight on how a select few can come to dominate many.
abstract: Viruses are a major cause of coccolithophore bloom demise in both temperate and sub-temperate oceanic regions. Most infection studies on coccolithoviruses have been conducted with a single virus strain, and the effect of intragenus competition by closely related coccolithoviruses has been ignored. Here we conducted combined infection experiments, infecting Emiliania huxleyi CCMP 2090 with two coccolithoviruses: EhV-86 and EhV-207 both simultaneously and independently. EhV-207 displayed a shorter lytic cycle and increased production potential than EhV-86 and was remarkably superior under competitive conditions. Although the viruses displayed identical adsorption kinetics in the first 2 h post infection, EhV-207 gained a numerical advantage as early as 8 h post infection. Quantitative polymerase chain reaction (PCR) revealed that when infecting in combination, EhV-207 was not affected by the presence of EhV-86, whereas EhV-86 was quickly out-competed, and a significant reduction in free and cell-associated EhV-86 was seen as early as 2 days after the initial infection. The observation of such clear phenotypic differences between genetically distinct, yet similar, coccolithovirus strains, by flow cytometry and quantitative real-time PCR allowed tentative links to the burgeoning genomic, transcriptomic and metabolic data to be made and the factors driving their selection, in particular to the de novo coccolithovirus-encoded sphingolipid biosynthesis pathway. This work illustrates that, even within a family, not all viruses are created equally, and the potential exists for relatively small genetic changes to infer disproportionately large competitive advantages for one coccolithovirus over another, ultimately leading to a few viruses dominating the many.
authors.affiliation: Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth, PL1 3DH, UK.
authors.forename: Jozef I
authors.initials: JI
authors.lastname: Nissimov
authors.affiliation: Department of Biological Chemistry, Rothamsted Research, Harpenden, Herts, AL5 2JQ, UK.
authors.forename: Johnathan A
authors.initials: JA
authors.lastname: Napier
authors.affiliation: Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth, PL1 3DH, UK.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Allen
authors.affiliation: Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth, PL1 3DH, UK.
authors.forename: Susan A
authors.initials: SA
authors.lastname: Kimmance
mesh_terms: D005434:Flow Cytometry; D018628:Gene Dosage / Q000235:genetics; D023281:Genomics; D058087:Haptophyta / Q000254:growth & development / Q000821:virology*; D017862:Phycodnaviridae / Q000145:classification / Q000235:genetics* / Q000502:physiology*; D016133:Polymerase Chain Reaction; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013107:Sphingolipids / Q000096:biosynthesis; D014779:Virus Replication / Q000235:genetics*
chemical_list: D013107:Sphingolipids