Nanoviridae


Nanoviridae is a family of viruses. Plants serve as natural hosts. The family contains 2 genera. Diseases associated with this family include: stunting.

Taxonomy

The recognized genera are:Babuvirus

Virus structure and genome

Viruses in the family Nanoviridae are non-enveloped, with icosahedral and round geometries, and T=1 symmetry. The diameter is around 18–19 nm.
GenusStructureSymmetryCapsidGenomic arrangementGenomic segmentation
NanovirusIcosahedralT=1Non-envelopedCircularSegmented
BabuvirusIcosahedralT=1Non-envelopedCircularSegmented

Life cycle

Viral replication is nuclear. Entry into the host cell is achieved by penetration into the host cell. Replication follows the ssDNA rolling circle model. After infection of a host cell, the small DNA molecules that have become encapsidated with the genomic ssDNA act as primers. They bind to complementary regions and help in initiation of DNA synthesis by host polymerases. On completion of synthesis, there will be a double stranded intermediate that is transcribed unidirectionally. Most individual nanovirus particles only encode for a single protein.
DNA-templated 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. The virus is transmitted via a vector.
GenusHost detailsTissue tropismEntry detailsRelease detailsReplication siteAssembly siteTransmission
NanovirusPlants: legumesPhloemViral movement; mechanical inoculationSecretion; viral movementNucleusNucleusAphids
BabuvirusPlants: musa speciesPhloemViral movement; mechanical inoculationSecretion; viral movementNucleusNucleusAphids