Journal Article

Spindle-shaped viruses infect marine ammonia-oxidizing thaumarchaea

Kim, So-Jeong, Yu, Woon-Jong, Gwak, Joo-Han, Rhee, Sung-Keun, Kim, Jong-Geol, Krupovic, Mart, Cho, Jang-Cheon, Cvirkaite-Krupovic, Virginija, Rodriguez-Valera, Francisco, López-Pérez, Mario

2019

Overview

Ammonia-oxidizing archaea (AOA) fromthe phylum Thaumarchaeota are ubiquitous in marine ecosystems and play a prominent role in carbon and nitrogen cycling. Previous studies have suggested that, like allmicrobes, thaumarchaea are infected by viruses and that viral predation has a profound impact on thaumarchaeal functioning and mortality, thereby regulating global biogeochemical cycles. However, not a single virus capable of infecting thaumarchaea has been reported thus far. Here we describe the isolation and characterization of three Nitrosopumilus spindle-shaped viruses (NSVs) that infect AOA and are distinct from other known marine viruses. Although NSVs have a narrow host range, they efficiently infect autochthonous Nitrosopumilus strains and display high rates of adsorption to their host cells. The NSVs have linear double-stranded DNA genomes of ∼28 kb that do not display appreciable sequence similarity to genomes of other known archaeal or bacterial viruses and could be considered as representatives of a new virus family, the “Thaspiviridae.” Upon infection, NSV replication leads to inhibition of AOA growth, accompanied by severe reduction in the rate of ammonia oxidation and nitrite reduction. Nevertheless, unlike in the case of lytic bacteriophages, NSV propagation is not associated with detectable degradation of the host chromosome or a decrease in cell counts. The broad distribution of NSVs in AOA-dominated marine environments suggests that NSV predation might regulate the diversity and dynamics of AOA communities. Collectively, our results shed light on the diversity, evolution, and potential impact of the virosphere associated with ecologically important mesophilic archaea.

• Publisher: National Academy of Sciences
• Subject: Ammonia / Ammonia - metabolism / Aquatic Organisms - genetics / Aquatic Organisms - metabolism / Aquatic Organisms - virology / Archaea / Archaea - genetics / Archaea - metabolism / Archaea - virology / Bacteriophages - physiology / Biodegradation / Biodiversity / Biogeochemical cycles / Biological Sciences / Carbon cycle / Chromosomes / Deoxyribonucleic acid / DNA / DNA, Archaeal - genetics / DNA, Archaeal - metabolism / Genomes / Host range / Life Sciences / Marine ecosystems / Marine environment / Mesophilic archaea / Microbiology / Microbiology and Parasitology / Nitrogen cycle / Nucleotide sequence / Oxidation / Phages / Predation / Reduction / Virology / Virus Replication / Viruses