Plasmaviridae
Plasmaviridae is a family of bacteria-infecting viruses. Acholeplasma species serve as natural hosts. There are currently only one genus (Plasmavirus), and one species in this family: the type species Acholeplasma virus L2.[1][2][3] All viruses known in this family have been isolated from species in the class Mollicutes.
| Plasmaviridae | |
|---|---|
 | |
| EM of a plasmavirus | |
Virus classification  | |
| (unranked): | Virus |
| Realm: | incertae sedis |
| Kingdom: | incertae sedis |
| Phylum: | incertae sedis |
| Class: | incertae sedis |
| Order: | incertae sedis |
| Family: | Plasmaviridae |
| Genera | |
| |
This family is poorly studied and little is known about the diversity and biology of these viruses.
Taxonomy
The family has one genus, Plasmavirus, which has one recognized member. There are five tentative members of Plasmavirus:
- Acholeplasma phage L2 (type species)
- Mycoplasmatales virus-laidlawii 1 (L1) (tentative)
- Mycoplasmatales virus-laidlawii 2 (L2) (tentative)
- Mycoplasmatales virus-laidlawii 3 (L3) (tentative)
- Mycoplasmatales virus-laidlawii 51 (L51) (tentative)
- Mycoplasmatales virus-laidlawii O1 (O1) (tentative)
Group: dsDNA
- Family: Plasmaviridae
- Genus: Plasmavirus
- Acholeplasma phage L2
Genome
The genome is condensed, nonsegmented and consists of a single molecule of circular, supercoiled double-stranded DNA, 12 kilobase pairs in length. The genome has a rather high G-C content of ~32%.[4] The genome has 14 open reading frames,[2] and encodes at least 15 proteins, of which at least four are structural proteins embedded in the membrane.
Structure
Virions are quasi-spherical, slightly pleomorphic, enveloped and about 80 nm (range 50–125 nm) in diameter.[1]
| Genus | Structure | Symmetry | Capsid | Genomic arrangement | Genomic segmentation |
|---|---|---|---|---|---|
| Plasmavirus | Spherical to pleomorphic | Undefined | Enveloped | Circular | Monopartite |
Life cycle
Viral replication is cytoplasmic. DNA-templated transcription is the method of transcription. The virus exits the host cell by budding. Acholeplasma species serve as the natural host.[2]
| Genus | Host details | Tissue tropism | Entry details | Release details | Replication site | Assembly site | Transmission |
|---|---|---|---|---|---|---|---|
| Plasmavirus | Bacteria: Acholeplasma sp. | None | Fusion | Membrane budding | Cytoplasm | Unknown | Unknown |
Infection
A productive infectious cycle begins before a lysogenic cycle establishes the virus in the infected bacteria. After initial infection of the viral genome the virus may become latent within the host. Lysogeny involves integration into the host chromosome.
References
- Krupovic, M; ICTV Report Consortium (May 2018). "ICTV Virus Taxonomy Profile: Plasmaviridae". The Journal of General Virology. 99 (5): 617–618. doi:10.1099/jgv.0.001060. PMID 29611799.
- "Viral Zone". ExPASy. Retrieved 15 June 2015.
- ICTV. "Virus Taxonomy: 2014 Release". Retrieved 15 June 2015.
- Büchen-Osmond, C. (Ed) (2003). 00.053. Plasmaviridae. In: ICTVdB—The Universal Virus Database, version 3. Büchen-Osmond, C. (Ed), ICTVdB Management, The Earth Institute and Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA.