Potyviridae is a family of positive-strand RNA viruses that encompasses more than 30% of known plant viruses,[1][2] many of which are of great agricultural significance. The family has 12 genera and 235 species, three of which are unassigned to a genus.[3][4][5][6]
Potyvirid virions are nonenveloped, flexuous filamentous, rod-shaped particles. The diameter is around 11–20 nm, with a length of 650–950 nm.[4][5]
Genomes are linear and usually nonsegmented, around 8–12kb in length,[4][5] consisting of positive-sense RNA, which is surrounded by a protein coat made up of a single viral encoded protein called a capsid. All induce the formation of virus inclusion bodies called cylindrical inclusions (‘pinwheels’) in their hosts. These consist of a single protein (about 70 kDa) made in their hosts from a single viral genome product.[citation needed]
Member viruses encode large polypeptides that are cleaved into mature proteins. In 5'–3' order these proteins are
There may be some variation in the number of the proteins depending on the genera and species.[7] For instance some genera lack P1, some virus of the genus Ipomovirus lack HC and have a P1 tandem. Pretty interesting sweet potato potyviral ORF (PISPO), alkylation B (AlkB), and inosine triphosphate pyrophosphatase (known as ITPase or HAM1) are protein domains identified in atypical members.[7][8]
Viral replication is cytoplasmic. Entry into the host cell is achieved by penetration. Replication follows the positive-stranded RNA virus replication model. Positive-stranded RNA virus transcription is the method of transcription. Translation takes place by −1 ribosomal frameshifting. The virus exits the host cell by tubule-guided viral movement.[4][5] Plants serve as the natural host. The virus is transmitted via a vector (often an insect or mite). Transmission routes are vector and mechanical.[4][5]