Tobamovirus

Tobamovirus
Electron micrograph of Tobacco mosaic virus particles at 160,000x magnification
Virus classification
Group: Group IV ((+)ssRNA)
Order: Unassigned
Family: Virgaviridae
Genus: Tobamovirus
Type species
Tobacco mosaic virus

The genus Tobamovirus contains viruses with a positive sense RNA genome that infect plants. The most common tobamovirus is probably tobacco mosaic virus, which infects tobacco and other plants including potato, tomato, and squash. The name Tobamovirus is an acronym, coming from the host and symptoms of the first virus discovered (Tobacco mosaic virus). There are four subgroups within this genus; the brassicas, cucurbits, malvaceous and solanaceous infecting tobamoviruses. The main differences between these groups are genome sequence and range of host plants.

Evolution

These viruses are thought to have codiverged with their hosts from a common ancestor.[1] There are at least 3 clades of virus: one infecting solanaceous species; a second infecting cucurbits and legumes and a third infecting the crucifers.[2]

Genome

The RNA genome encodes four polypeptides; the non-structural protein and the read through product which are involved in virus replication, the movement protein which is necessary for the virus to move between cells and the coat protein. The virus is able to replicate without the movement or coat proteins but the other two are essential. The non-structural protein has domains suggesting it is involved in RNA capping and the read through product has a motif for an RNA polymerase. The movement proteins are made very early in the infection cycle and localized to the plasmodesmata, they are probably involved in host specificity as they are believed to interact with some host cell factors.

Routes of Infection

The infection is localized to begin with but if the virus remains unchallenged it will spread via the vascular system into a systemic infection. The exact mechanism the virus uses to move throughout the plant is unknown but the interaction of pectin methylesterase, a cellular enzyme important for cell wall metabolism and plant development, with the movement protein has been implicated.[3]

Species

Definitive members of the Tobamovirus genus:[4]

  • Bell pepper mosaic virus (BPeMV)
  • Brugmansia mild mottle virus
  • Cactus mild mottle virus (CMMoV)[5]
  • Clitoria yellow mottle virus
  • Cucumber fruit mottle mosaic virus
  • Cucumber green mottle mosaic virus (CGMMV)
  • Cucumber mottle virus
  • Frangipani mosaic virus (FrMV)
  • Hibiscus latent Fort Pierce virus (HLFPV)
  • Hibiscus latent Singapore virus (HLSV)
  • Kyuri green mottle mosaic virus
  • Maracuja mosaic virus (MarMV)
  • Obuda pepper virus (ObPV)
  • Odontoglossum ringspot virus (ORSV)
  • Paprika mild mottle virus
  • Passion fruit mosaic virus
  • Pepper mild mottle virus (PMMoV)
  • Rattail cactus necrosis-associated virus (RCNaV)
  • Rehmannia mosaic virus
  • Ribgrass mosaic virus (HRV)
  • Sammons's Opuntia virus (SOV)
  • Streptocarpus flower break virus
  • Sunn-hemp mosaic virus (SHMV)
  • Tobacco latent virus
  • Tobacco mild green mosaic virus
  • Tomato mosaic virus (ToMV) and U2 - Tobacco mosaic virus (T2MV)
  • Tomato mottle mosaic virus
  • Tropical soda apple mosaic virus
  • Turnip vein-clearing virus (TVCV)
  • Ullucus mild mottle virus
  • Wasabi mottle virus (WMoV)
  • Yellow tailflower mild mottle virus
  • Youcai mosaic virus (YoMV) aka oilseed rape mosaic virus (ORMV)
  • Zucchini green mottle mosaic virus

Tentative members of the Tobamovirus genus include:[4]

This list is incomplete; you can help by expanding it.

References

  1. ↑ Stobbe, A. H.; Melcher, U.; Palmer, M. W.; Roossinck, M. J.; Shen, G. (2011). "Co-divergence and host-switching in the evolution of tobamoviruses". Journal of General Virology 93 (2): 408–418. doi:10.1099/vir.0.034280-0. PMID 22049092.
  2. ↑ Lartey, R. T.; Voss, T. C.; Melcher, U. (1996). "Tobamovirus evolution: Gene overlaps, recombination, and taxonomic implications". Molecular biology and evolution 13 (10): 1327–1338. doi:10.1093/oxfordjournals.molbev.a025579. PMID 8952077.
  3. ↑ Chen, M. H.; Citovsky, V. (2003). "Systemic movement of a tobamovirus requires host cell pectin methylesterase". The Plant Journal 35 (3): 386–392. doi:10.1046/j.1365-313X.2003.01818.x. PMID 12887589.
  4. ↑ 4.0 4.1 "Descriptions of Plant Viruses: Tobamovirus Group". The Association of Applied Biologists (AAB).
  5. ↑ Min, B. E.; Chung, B. N.; Kim, M. J.; Ha, J. H.; Lee, B. Y.; Ryu, K. H. (2005). "Cactus mild mottle virus is a new cactus-infecting tobamovirus". Archives of Virology 151 (1): 13–21. doi:10.1007/s00705-005-0617-7. PMID 16132178.

External links