Viruses in Nepovirus are non-enveloped, with icosahedral geometries, and T=pseudo3 symmetry. The diameter is around 28-30 nm. Genomes are linear and segmented, bipartite, around 23.9kb in length.[1]
Genus
Structure
Symmetry
Capsid
Genomic arrangement
Genomic segmentation
Nepovirus
Icosahedral
Pseudo T=3
Non-enveloped
Linear
Segmented
Life cycle
Viral replication is cytoplasmic. Entry into the host cell is achieved by penetration into the host cell. Replication follows the positive stranded RNA virus replication model. Positive stranded RNA virus transcription is the method of transcription. The virus exits the host cell by tubule-guided viral movement.
Plants serve as the natural host. The virus is transmitted via a vector (nematodes, mite, and thrips). Transmission routes are vector.[1]
Genus
Host details
Tissue tropism
Entry details
Release details
Replication site
Assembly site
Transmission
Nepovirus
Plants
None
Viral movement; mechanical inoculation
Viral movement
Cytoplasm
Cytoplasm
Nematodes; mites; thrips
Genome
Nepoviruses are classified as type IV viruses under the Baltimore classification system, and consequently contain bipartite, linear, single stranded positive sense RNAgenomes. The two genome segments are encapsulated separately into two different icosahedral particles. Each of the genome segments produces a different polypeptide, which undergoes a series of steps (i.e. proteolysis, and other post-translational modifications) in order to produce a functional protein.[3]
RNA1
The first segment (RNA1) is approximately 8,000 nucleotides in length and appears as a single copy in each B type virion. It encodes the proteins that are important in replication and is the first gene to be activated.[3]
RNA2
The second segment (RNA2) is approximately 4,000–7,000 nucleotides in length and usually appears as a single copy in each M type virion. It encodes the proteins that are important in cell-cell transmission and evasion of cellular defenses.[3]
