Petuvirus

Petuvirus is a genus of viruses, in the family Caulimoviridae order Ortervirales. Plants serve as natural hosts. There is currently only one species in this genus: the type species Petunia vein clearing virus. Diseases associated with this genus include: plants: chlorotic vein clearing, leaf malformation. Group: ssRNA-RT Petuviruses (including other members of the Caulimovirusus such as soymoviruses and Cavemoviruses) form isometric particles whereas members of Badnaviruses and Tungroviruses have bacilliform virus particles. Viruses in Petuvirus are non-enveloped, with icosahedral geometries, and T=7 symmetry. The diameter is around 45-50 nm. Genomes are circular and non-segmented. Its genome is 7200 nucleotides long and has a guanine + cytosine content of 38.2%. There are terminally redundant sequences on the genome which have direct terminal repeats that are reiterated internally in inverted form. The virus codes for 2 ORFs. Its capsid shells are multilayered. The capsid is round to elongate with icosahedral symmetry and the virus is composed of 16% nucleic acid. Petuviruses have a buoyant density in CsCl of 1.31 g cm-3 and there are 1 sedimenting component(s) found in purified preparations. The sedimentation coefficient is 218–251.5–285 S20w while the thermal inactivation point (TIP) is at 55–57.5–60 °C. Viral replication is nuclear/cytoplasmic. Entry into the host cell is achieved by attachment of the viral proteins to host receptors, which mediates endocytosis. Replication follows the dsDNA(RT) replication model. DNA-templated transcription, specifically dsDNA(RT) transcription is the method of transcription. The virus exits the host cell by nuclear pore export, and tubule-guided viral movement.Plants serve as the natural host. Transmission routes are mechanical and grafting.