Virus phyla

Nucleocytoviricota is a phylum of viruses. Members of the phylum are also known as the nucleocytoplasmic large DNA viruses (NCLDV), which serves as the basis of the name of the phylum with the suffix - for virus phylum. These viruses are referred to as nucleocytoplasmic because they are often able to replicate in both the host's cell nucleus and cytoplasm.

Pisuviricota is a phylum of RNA viruses that includes all positive-strand and double-stranded RNA viruses that infect eukaryotes and are not members of the phyla Kitrinoviricota, Lenarviricota or Duplornaviricota. The name of the group is a syllabic abbreviation of “picornavirus supergroup” with the suffix -viricota, indicating a virus phylum. Phylogenetic analyses suggest that Birnaviridae and Permutotetraviridae, both currently unassigned to a phylum in Orthornavirae, also belong to this phylum and that both are sister groups.

Cressdnaviricota is a phylum of viruses with small, circular single-stranded DNA genomes and encoding rolling circle replication-initiation proteins with the N-terminal HUH endonuclease and C-terminal superfamily 3 helicase domains. While the replication-associated proteins are homologous among viruses within the phylum, the capsid proteins are very diverse and have presumably been acquired from RNA viruses on multiple independent occasions. Nevertheless, all cressdnaviruses for which structural information is available appear to contain the jelly-roll fold.

Lenarviricota is a phylum of RNA viruses that includes all positive-strand RNA viruses that infect prokaryotes. Some members also infect eukaryotes. Most of these viruses do not have capsids, except for the genus Ourmiavirus. The name of the group is a syllabic abbreviation of the names of founding member families "Leviviridae and Narnaviridae" with the suffix -viricota, denoting a virus phylum.

Preplasmiviricota is a phylum of viruses. Its name means "precursor of certain plasmids".

Kitrinoviricota is a phylum of RNA viruses that includes all positive-strand RNA viruses that infect eukaryotes and are not members of the phylum Pisuviricota or Lenarviricota. The name of the group derives from Greek κίτρινος (kítrinos), which means yellow (a reference to yellow fever virus), and -viricota, which is the suffix for a virus phylum.

Duplornaviricota is a phylum of RNA viruses, which contains all double-stranded RNA viruses, except for those in phylum Pisuviricota. Characteristic of the group is a viral capsid composed of 60 homo- or heterodimers of capsid protein on a pseudo-T=2 lattice. Duplornaviruses infect both prokaryotes and eukaryotes. The name of the group derives from Italian duplo which means double (a reference to double-stranded), rna for the type of virus, and -viricota which is the suffix for a virus phylum.