title: Petuvirus
text: # Petuvirus
  
  Petuvirus is a genus of viruses, in the family Caulimoviridae order Ortervirales. Plants serve as natural hosts. There is only one species in this genus: Petunia vein clearing virus. Diseases associated with this genus include: plants: chlorotic vein clearing, leaf malformation.
  
  ## Structure
  
  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.
  
  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.
  
  | Genus | Structure | Symmetry | Capsid | Genomic arrangement | Genomic segmentation |
  | - | - | - | - | - | - |
  | Petuvirus | Icosahedral | T=7 | Non-enveloped | Circular | Monopartite |
  
  ## Life cycle
  
  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.
  
  | Genus | Host details | Tissue tropism | Entry details | Release details | Replication site | Assembly site | Transmission |
  | - | - | - | - | - | - | - | - |
  | Petuvirus | Plants | None | Viral movement; mechanical inoculation | Viral movement | Nucleus | Cytoplasm | Grafting |
  