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: Jozef I Nissimov, Johnathan A Napier, Michael J Allen, Susan A Kimmance
• Journal: Environmental microbiology (Environ Microbiol) Vol. 18 Issue 1 Pg. 133-45 (Jan 2016) ISSN: 1462-2920 [Electronic] England
• PMID: 25970076 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Chemical References

• Sphingolipids

Topics

• Flow Cytometry
• Gene Dosage (genetics)
• Genomics
• Haptophyta (growth & development, virology)
• Phycodnaviridae (classification, genetics, physiology)
• Polymerase Chain Reaction
• Real-Time Polymerase Chain Reaction
• Sequence Analysis, DNA
• Sphingolipids (biosynthesis)
• Virus Replication (genetics)