Geminiviridae

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Geminiviridae
Good msv 3.jpg

Purified Maize streak virus (MSV),
the scale corresponds to 50 nm.

Systematics
Classification : Viruses
Area : Monodnaviria
Empire : Shotokuvirae
Phylum : Cressdnaviricota
Class : Repensiviricetes
Order : Plugged viral
Family : Geminiviridae
Taxonomic characteristics
Genome : (+/-) ssDNA circular
Baltimore : Group 2
Symmetry : dimer icosahedral
Cover : no
Scientific name
Geminiviridae
Left
NCBI  Taxonomy: 10811
ViralZone ( ExPASy , SIB): 109

The Geminiviridae are a family of DNA viruses that infect various plant species . They are transmitted by various insects . They are pathogens of agricultural importance.

construction

Virion

Schematic drawing of the gemini viruses.

The virions (virus particles) of the geminiviruses have an unenveloped capsid which is approximately 38 nm in length  and approximately 22 nm in diameter. The capsid has a constriction along half of the long side. The constriction divides the capsid into two roughly equal halves of icosahedral structure with a triangulation number of one, from which the name Geminiviridae ( Latin gemini , twins ) comes. The viral single-stranded (+) - strand DNA is packaged in the capsid in the nucleus of the host cell.

Genome

Geminiviruses have - as circoviruses and nanoviruses - a comparatively small genome of a single-stranded circular DNA molecule having ambisense - polarity of about 2.5-3.1 kilobases in length with two opposite open reading frames . With some begomoviruses (e.g. AbMV) the genome is in two parts ( English bipartite ) with two DNA strands of 2.6–2.8 kilobases each, which is why an infection can only occur with two begomoviruses with different genome halves. Geminiviruses may originate from a plasmid of Phytoplasma spp. originated. The genomes of the geminiviruses can recombine if two or more geminiviruses are co-infected . The genome is replicated by the host cell's DNA polymerase in the nucleus of a plant cell using rolling circle replication . The viral protein Rep cuts the viral DNA at the origin of replication and thus initiates replication. Replication starts at inverted repeats in the conserved sequence TAATATTAC, possibly a stem loop - secondary structure is formed.

Proteins

The genome codes for the proteins Rep and CP (from English coat protein , envelope protein ). Rep is an endonuclease and initiates replication of the viral genome. CP is the capsid protein and is an essential component in the replication of the genome.

Replication cycle

After being absorbed into the cell, geminiviruses are transported from the cytosol into the cell nucleus by importing the nucleus. There Rep initiates the replication of the viral DNA by the DNA polymerase of the host cell with the participation of the CP and the transcription . The viral mRNA is channeled into the cytosol, where the viral proteins are produced on the ribosome . The viral proteins are transported into the cell nucleus, accumulate and bind viral DNA, whereby the virions are formed. The viruses leave the cell by budding, among other things. It is not yet clear to what extent the transmission takes place through virions or through desmosomes through viral DNA with bound CP .

Systematics

The Geminiviridae is the largest family of single-stranded DNA viruses. The mastreviruses by various cicadas transmit such. B. The Maize streak virus and African streak viruses by Cicadulina mbila . Curtoviruses and topocuviruses are transmitted by humpback chirps , e.g. B. the tomato pseudo-curly top virus by Micrutalis malleifera . Begomoviruses are transmitted by the whitefly Bemisia tabaci .

The Geminiviridae family includes the following genera (type species are marked with (*)):

Suggested as further genera:

  • Genus ' Baminivirus '
  • Genus ' Nimivirus '
  • Genus ' Niminivirus '

Some geminiviruses have not yet been assigned to a gender:

  • Species Citrus chlorotic dwarf associated virus
  • Species Citrus chlorotic dwarf associated virus
  • Species ' Grapevine Cabernet Franc-associated virus ', alias ' Grapevine redleaf-associated virus ' or ' Grapevine red blotch-associated virus ', GRBaV

literature

  • GP Martelli et al. : Family Geminiviridae. In: AMQ King, MJ Adams, EB Carstens, EJ Lefkowitz (eds.): Virus Taxonomy. Ninth Report of the International Committee on Taxonomy of Viruses. Amsterdam 2012, ISBN 978-0-12-384684-6 .
  • DM Knipe, Peter M. Howley , DE Griffin, (Eds.): Fields Virology. 5th edition. Lippincott Williams & Wilkins, Philadelphia 2007, ISBN 978-0-7817-6060-7 .

Web links

Commons : Geminiviridae  - Collection of images, videos and audio files

Individual evidence

  1. ↑ a b c d e ICTV: ICTV Taxonomy history: Maize streak virus , EC 51, Berlin, Germany, July 2019; Email ratification March 2020 (MSL # 35)
  2. ^ SM Gray, N. Banerjee: Mechanisms of Arthropod Transmission of Plant and Animal Viruses . In: Microbiol Mol Biol Rev. Volume 63 , no. 1 , 1999, p. 128-148 , PMID 10066833 , PMC 98959 (free full text).
  3. ↑ M. Krupovic, JJ Ravantti, DH Bamford: Geminiviruses: a tale of a plasmid becoming a virus . In: BMC Evol Biol . tape 9 , 2009, p. 112 , doi : 10.1186 / 1471-2148-9-112 , PMID 19460138 , PMC 2702318 (free full text) - ( biomedcentral.com [PDF]).
  4. ↑ R. Chasan: Geminiviruses: A Twin Approach to Replication . In: Plant Cell . tape 7 , no. 6 , 1995, pp. 659-661 , doi : 10.1105 / tpc.7.6.659 ( plantcell.org [PDF]).
  5. ^ C. Gutierrez: NEW EMBO MEMBERS 'REVIEW: DNA replication and cell cycle in plants: learning from geminiviruses . In: EMBO . tape 19 , no. 5 , 2000, pp. 792-799 , doi : 10.1093 / emboj / 19.5.792 , PMID 10698921 , PMC 305619 (free full text).
  6. ↑ SIB: Begomovirus , on: ViralZone
  7. ↑ SIB: Curtovirus , on: ViralZone
  8. ↑ SIB: Mastrevirus , on: ViralZone
  9. ↑ SIB: Topocuvirus , on: ViralZone
  10. ↑ TF Ng, R. Marine, C. Wang, P. Simmonds, B. Kapusinszky, L. Bodhidatta, BS Oderinde, KE Wommack, E. Delwart: High variety of known and new RNA and DNA viruses of diverse origins in untreated sewage . In: J Virol. 6 (22), 2012, pp. 12161-12175. doi: 10.1128 / JVI.00869-12
  11. ↑ S. Poojari, OJ Alabi, VY Fofanov, RA Naidu: A leafhopper-transmissible DNA virus with novel evolutionary lineage in the family geminiviridae implicated in grapevine redleaf disease by next-generation sequencing . In: PLoS One. 8 (6), 2013, p. E64194. doi: 10.1371 / journal.pone.0064194
  12. ↑ Red Blotch Rising - Seven Fifty Daily . February 6, 2019. Retrieved March 22, 2018.
  13. ^ Cornell and UC Davis Identify a New Virus Associated with Red Blotch Disease - Viticulture and Enology . Retrieved February 6, 2019.