THE INTERNATIONAL COMMITTEE ON TAXONOMY OF VIRUSES HAS ADOPTED A BINOMIAL NOMENCLATURE FOR VIRUS SPECIES: AN UPDATE OF PLANT INFECTING VIRUSES IN THE PHYLUM NEGARNAVIRICOTA

The International Committee on Taxonomy of Viruses (ICTV) is responsible for developing and maintaining an internationally agreed system of hierarchical classification of viruses and naming of taxa. The ICTV also oversees the classification of other mobile genetic elements including satellite nucleic acids, viriforms and viroids. Over time the taxonomic framework has been adapted to the current knowledge on the evolution of virosphere. The ICTV now allows the classification of viruses known only from genome sequences obtained by metagenomic analyses. Taxonomic ranks have been expanded beyond orders up to realms, to include eight primary ranks (realm, kingdom, phylum, class, order, family, genus and species) and seven secondary ranks (subrealm, subkingdom, subphylum, subclass, suborder, subfamily and subgenus), paving the way to comprehensive studies on evolutionary connections of viruses. To align virus taxonomy to other taxonomies, the ICTV recognized the need for a standardized, uniform nomenclature for virus species a long time ago and, after years of internal and public debates, a binomial nomenclature for virus species was ratified by the ICTV in the 2021 vote. Thus, a virus species name will consist of two italicized words, the first one being the genus name and the second one consisting of a "freeform" species epithet. In this framework, Linnaean-style, Latinized virus species are permitted, but not mandated. The species names can be composed using the standard Latin-script English alphabet containing 26 letters and/or Arabic numbers. Starting 2021, newly created virus species names adopted a binomial format. The process of renaming all current species has been completed and ratified early in 2024. Very importantly, this process involves virus species names only. The common virus name will remain unchanged. A taxonomy update is given of the plant infecting viruses classified in the phylum Negarnaviricota.