Sobemovirus


Sobemovirus is a genus of non-enveloped, positive-strand RNA viruses which infect plants. Plants serve as natural hosts. There are 26 species in this genus. Diseases associated with this genus include: mosaics and mottles.

Structure

Viruses in Sobemovirus are non-enveloped, with icosahedral geometries, and T=3 symmetry. The diameter is around 30 nm.
GenusStructureSymmetryCapsidGenomic arrangementGenomic segmentation
SobemovirusIcosahedralT=3Non-envelopedLinearMonopartite

Genome

The genome is a single piece of linear, positive-sense, single-stranded RNA, 4,000–4,500 nucleotides in length. The genome encodes five open reading frames: ORF1, ORFs 2a and 2b, ORF3 and ORFx.
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.
ORF3 encodes the coat protein.
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.

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. 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. Transmission routes are vector and seed borne.
GenusHost detailsTissue tropismEntry detailsRelease detailsReplication siteAssembly siteTransmission
SobemovirusPlants-PenetrationViral MovementCytoplasmCytoplasmVector, Seed borne

Taxonomy

The genus includes the following species, listed by scientific name and followed by the exemplar virus of the species:Sobemovirus ARTVA, Artemisia virus ASobemovirus BSSV, Blueberry shoestring virusSobemovirus CFMV, Cocksfoot mottle virusSobemovirus CNMOV, Cynosurus mottle virusSobemovirus CYCMV, Cymbidium chlorotic mosaic virusSobemovirus IYMV, Imperata yellow mottle virusSobemovirus LTSV, Lucerne transient streak virusSobemovirus MIMMV, Sobemovirus MIMMVSobemovirus PHYRMV, Physalis rugose mosaic virusSobemovirus PISSV, Pistacia sobemovirusSobemovirus PLSV, Poaceae Liege sobemovirusSobemovirus PLYV, Papaya lethal yellowing virusSobemovirus RGMOV, Ryegrass mottle virusSobemovirus ROMOV, Rottboellia yellow mottle virusSobemovirus RYMV, Rice yellow mottle virusSobemovirus SBMV, Southern bean mosaic virusSobemovirus SCMOV, Subterranean clover mottle virusSobemovirus SCPMV, Southern cowpea mosaic virusSobemovirus SEMV, Sesbania mosaic virusSobemovirus SMAMV, Snake melon asteroid mosaic virusSobemovirus SNMOV, Solanum nodiflorum mottle virusSobemovirus SOMV, Sowbane mosaic virusSobemovirus SYCMV, Soybean yellow common mosaic virusSobemovirus TROV, Turnip rosette virusSobemovirus VTMOV, Velvet tobacco mottle virusSobemovirus XYDV, Xufa yellow dwarf virus