Sobemovirus is a genus of non-enveloped, positive-strand RNA viruses which infect plants. Plants serve as natural hosts. There are 21 species in this genus. Diseases associated with this genus include: mosaics and mottles.[1][2]
Structure
Viruses in Sobemovirus are non-enveloped, with icosahedral geometries, and T=3 symmetry. The diameter is around 30 nm.[1]
Genus
Structure
Symmetry
Capsid
Genomic arrangement
Genomic segmentation
Sobemovirus
Icosahedral
T=3
Non-enveloped
Linear
Monopartite
Genome
The genome of sobemoviruses exemplified by Sesbania mosaic virus.
The genome is a single piece of linear, positive-sense, single-stranded RNA, 4,100–5,700 nucleotides in length.[3] The genome encodes five open reading frames: ORF1, ORFs 2a and 2b, ORF3 and ORFx.[4]
ORF1 encodes P1 which plays a role in suppression of silencing and virus movement.
ORFs 2a and 2b encode the replicational polyproteins P2a and P2ab. Translation of ORF2a from the genomic RNA is dependent on a leaky scanning mechanism.[citation needed]
ORFx is conserved in all sobemoviruses. It overlaps the 5' end of ORF2a in the +2 reading frame and also extends some distance upstream of ORF2a. It lacks an AUG initiation codon and its expression is predicted to depend on low level initiation at near-cognate non-AUG codons, such as CUG, by a proportion of the ribosomes that are scanning the region between the ORF1 and ORF2a initiation codons. Its function is unknown but it appears to be essential for infection.[citation needed]
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. Translation takes place by leaky scanning, and −1 ribosomal frameshifting. The virus exits the host cell by tubule-guided viral movement. Plants serve as the natural host. The virus is transmitted via a vector (CFMV: insects). Transmission routes are vector and seed borne.[1]
^ ab"Virus Taxonomy: 2022 Release". International Committee on Taxonomy of Viruses (ICTV). March 2023. Retrieved 10 August 2023.
^Index of Viruses—Sobemovirus (2006). In: ICTVdB—The Universal Virus Database, version 4. Büchen-Osmond, C (Ed), Columbia University, New York, USA.[page needed]
