Pleomorphic archaeal viruses: the family Pleolipoviridae is expanding by seven new species

Established in 2016, the family Pleolipoviridae comprises globally distributed archaeal viruses that produce pleomorphic particles. Pseudo-spherical enveloped virions of pleolipoviruses are membrane vesicles carrying a nucleic acid cargo. The cargo can be either a single-stranded or double-stranded DNA molecule, making this group the first family introduced in the 10(th) Report on Virus Taxonomy including both single-stranded and double-stranded DNA viruses. The length of the genomes is approximately 7–17 kilobase pairs, or kilonucleotides in the case of single-stranded molecules. The genomes are circular single-stranded DNA, circular double-stranded DNA, or linear double-stranded DNA molecules. Currently, eight virus species and seven proposed species are classified in three genera: Alphapleolipovirus (five species), Betapleolipovirus (nine species), and Gammapleolipovirus (one species). Here, we summarize the updated taxonomy of the family Pleolipoviridae to reflect recent advances in this field, with the focus on seven newly proposed species in the genus Betapleolipovirus: Betapleolipovirus HHPV3, HHPV4, HRPV9, HRPV10, HRPV11, HRPV12, and SNJ2.