Fig mosaic emaravirus

Last updated
Fig mosaic emaravirus
Fig Mosaic.jpg
Symptoms of fig mosaic on fig leaves
Virus classification OOjs UI icon edit-ltr.svg
(unranked): Virus
Realm: Riboviria
Kingdom: Orthornavirae
Phylum: Negarnaviricota
Class: Ellioviricetes
Order: Bunyavirales
Family: Fimoviridae
Genus: Emaravirus
Species:
Fig mosaic emaravirus
Synonyms
  • Fig mosaic virus

Fig mosaic emaravirus (FMV) is a segmented, negative sense, single-stranded RNA virus that is determined to be the causal agent of fig mosaic disease (FMD) in fig plants, Ficus carica . [1] It is a member of the genus Emaravirus [2] and order Bunyavirales and is transmitted mainly by the eriophyid mite Aceria ficus. [3] FMV can cause a range of symptoms varying in severity, including leaf chlorosis, deformity, and mosaic or discoloration patterns, as well as premature fruit drop. [4]

Contents

History

Fig mosaic disease (FMD) was first described and suspected to be of viral origin in 1933 by Ira J. Condit and W.T.Horne. [5] It was determined to be caused by a virus in 2009 by Jeewan Jyot Walia, Nida M. Salem, and Bryce W. Falk. [6] The disease and associated virus have since been observed in Greece, Italy, Spain, Turkey, Syria, Tunisia, Algeria, Jordan, New Zealand, China, Great Britain, Puerto Rico, Australia, and the United States. [6]

Classification

FMV has been placed in the genus Emaravirus, [7] which contains other single-stranded, negative-sense, segmented RNA plant viruses. Emaraviruses all contain four to six genome segments. They are also common in their mode of transmission, which is via various species of eriophyid mites by unknown mechanism as well as mechanical modes of transmission. [3] Besides FMV, the genus Emaravirus includes European mountain ash ringspot-associated emaravirus (EMARaV), Rose rosette emaravirus (RRV), Raspberry leaf blotch emaravirus (RLBV), and other species. [3]

Genome Structure

The FMV genome consists of segmented (multipartite) negative-sense, single-stranded RNA. [8] The genome has long been thought to have four segments, but recent findings have supported the existence of six RNA genome segments. [9] Each segment has one open reading frame (ORF). [3] The first segment, FMV vcRNA 1 (7093 nt), is common to all viruses of genus Emaravirus and codes for the virus's 264 kDa RNA-dependent RNA polymerase (RdRp), which has endonuclease activity near the N-terminus. The second segment, vcRNA2, (2252 nt) encodes a 73 kDa putative glycoprotein. FMV vcRNA3 (1490 nt) encodes a 35 kDa nucleocapsid (N) protein. FMV vcRNA4 (1472 nt) encodes a 40.5 kDa protein with function still unknown. [5] The two most recently discovered segments, RNA5 and RNA6, unlike the other four segments, are not highly conserved within the genus. Perhaps this is because they are truncated or defective, but the functions of the proteins they encode is still undetermined. [9]

Movement between and into cells (FMV-p4)

Like all plant viruses, FMV encodes a movement protein (MP) to enable it to move between cells, usually by increasing the size exclusion limits (SEL) of plasmodesmata to allow viral passage. [10] FMV's MP is most likely p4, an inference that is supported by its localization in the plasma membrane but has not been definitively shown yet. [3]

Genome replication via cap snatching

FMV vcRNA 1 codes for RNA dependent RNA polymerase protein (RdRp), which has endonuclease function at its N terminus and is packaged in the virion. Once the virion has entered a cell, RdRp binds to host mRNA and uses endonuclease activity to cleave the 5’ methylated cap for use as a primer for mRNA synthesis and as a way to hijack host translational machinery [5]

DMBs and LFPs

Infection with FMV results in distinct double-membrane bodies or particles, called DMBs or DMPs, 90-200 nm in diameter in the cytosol of infected parenchyma cells. [6] [8] [11] These double membrane-bound bodies are surrounded by a fibril matrix and found only in leaves showing mosaic symptoms at a macro level, never in the uninfected tissue used as a control. [11] Some cultivars have also shown long, flexuous, rod-shaped, virus-like particles (LFPs) in tissues showing signs of necrosis. These are also not seen in uninfected control tissues. [11] Neither type has a determined function.

Symptoms

FMV results in a variety of symptoms, some of which could have strong agricultural detriment, such as decreased fruit yield. Symptoms include appearance of a leaf mosaic pattern, defoliation, decreased fruit yield, vein banding, ringspots, distortion and chlorosis of leaves, and yellow spotting on fruits. [6] [9]

Unknowns and future research

There are still many aspects of this virus’ molecular structure and function that are unknown. The protein encoded by the fourth segment on the viral genome, RNA4, still has an unknown function. [5] Additionally, the exact molecular mechanisms of FMV's replication, and Emaravirus replication in general, are still not confirmed. [4] Current research is also working on learning more about the nature of DMBs/DMPs, as they are difficult to isolate from infected plants. [6]

Related Research Articles

<span class="mw-page-title-main">RNA virus</span> Subclass of viruses

An RNA virus is a virus—other than a retrovirus—that has ribonucleic acid (RNA) as its genetic material. The nucleic acid is usually single-stranded RNA (ssRNA) but it may be double-stranded (dsRNA). Notable human diseases caused by RNA viruses include the common cold, influenza, SARS, MERS, COVID-19, Dengue Virus, hepatitis C, hepatitis E, West Nile fever, Ebola virus disease, rabies, polio, mumps, and measles.

<i>Flaviviridae</i> Family of viruses

Flaviviridae is a family of enveloped positive-strand RNA viruses which mainly infect mammals and birds. They are primarily spread through arthropod vectors. The family gets its name from the yellow fever virus; flavus is Latin for "yellow", and yellow fever in turn was named because of its propensity to cause jaundice in victims. There are 89 species in the family divided among four genera. Diseases associated with the group include: hepatitis (hepaciviruses), hemorrhagic syndromes, fatal mucosal disease (pestiviruses), hemorrhagic fever, encephalitis, and the birth defect microcephaly (flaviviruses).

Virus classification is the process of naming viruses and placing them into a taxonomic system similar to the classification systems used for cellular organisms.

<span class="mw-page-title-main">Sedoreoviridae</span> Family of viruses

Sedoreoviridae is a family of double-stranded RNA viruses. Member viruses have a wide host range, including vertebrates, invertebrates, plants, protists and fungi. They lack lipid envelopes and package their segmented genome within multi-layered capsids. Lack of a lipid envelope has allowed three-dimensional structures of these large complex viruses to be obtained, revealing a structural and likely evolutionary relationship to the cystovirus family of bacteriophage. There are currently 97 species in this family, divided among 15 genera in two subfamilies. Reoviruses can affect the gastrointestinal system and respiratory tract. The name "reo-" is an acronym for "respiratory enteric orphan" viruses. The term "orphan virus" refers to the fact that some of these viruses have been observed not associated with any known disease. Even though viruses in the family Reoviridae have more recently been identified with various diseases, the original name is still used.

<span class="mw-page-title-main">Satellite (biology)</span> Subviral agent which depends on a helper virus for its replication

A satellite is a subviral agent that depends on the coinfection of a host cell with a helper virus for its replication. Satellites can be divided into two major classes: satellite viruses and satellite nucleic acids. Satellite viruses, which are most commonly associated with plants, are also found in mammals, arthropods, and bacteria. They encode structural proteins to enclose their genetic material, which are therefore distinct from the structural proteins of their helper viruses. Satellite nucleic acids, in contrast, do not encode their own structural proteins, but instead are encapsulated by proteins encoded by their helper viruses. The genomes of satellites range upward from 359 nucleotides in length for satellite tobacco ringspot virus RNA (STobRV).

<span class="mw-page-title-main">Plant virus</span> Virus that affects plants

Plant viruses are viruses that affect plants. Like all other viruses, plant viruses are obligate intracellular parasites that do not have the molecular machinery to replicate without a host. Plant viruses can be pathogenic to vascular plants.

<i>Geminiviridae</i> Family of viruses

Geminiviridae is a family of plant viruses that encode their genetic information on a circular genome of single-stranded (ss) DNA. There are 520 species in this family, assigned to 14 genera. Diseases associated with this family include: bright yellow mosaic, yellow mosaic, yellow mottle, leaf curling, stunting, streaks, reduced yields. They have single-stranded circular DNA genomes encoding genes that diverge in both directions from a virion strand origin of replication. According to the Baltimore classification they are considered class II viruses. It is the largest known family of single stranded DNA viruses.

<i>Nanoviridae</i> Family of viruses

Nanoviridae is a family of viruses. Plants serve as natural hosts. There are currently 12 species in this family, divided among 2 genera and one unassigned species. Diseases associated with this family include: stunting. Their name is derived from the Greek word νᾶνος, because of their small genome and their stunting effect on infected plants.

<i>Bromoviridae</i> Family of viruses

Bromoviridae is a family of viruses. Plants serve as natural hosts. There are six genera in the family.

<i>Closteroviridae</i> Family of viruses

Closteroviridae is a family of viruses. Plants serve as natural hosts. There are four genera and 59 species in this family, seven of which are unassigned to a genus. Diseases associated with this family include: yellowing and necrosis, particularly affecting the phloem.

<i>Tombusviridae</i> Family of viruses

Tombusviridae is a family of single-stranded positive sense RNA plant viruses. There are three subfamilies, 17 genera, and 95 species in this family. The name is derived from Tomato bushy stunt virus (TBSV).

<i>Tobamovirus</i> Genus of viruses

Tobamovirus is a genus of positive-strand RNA viruses in the family Virgaviridae. Many plants, including tobacco, potato, tomato, and squash, serve as natural hosts. Diseases associated with this genus include: necrotic lesions on leaves. The name Tobamovirus comes from the host and symptoms of the first virus discovered.

Idaeovirus is a genus of positive-sense ssRNA viruses that contains two species: Raspberry bushy dwarf virus (RBDV) and Privet idaeovirus. RBDV has two host-dependent clades: one for raspberries; the other for grapevines. Infections are a significant agricultural burden, resulting in decreased yield and quality of crops. RBDV has a synergistic relation with Raspberry leaf mottle virus, with co-infection greatly amplifying the concentration of virions in infected plants. The virus is transmitted via pollination with RBDV-infected pollen grains that first infect the stigma before causing systemic infection.

<i>Sobemovirus</i> Genus of viruses

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.

<i>Picobirnavirus</i> Genus of viruses

Picobirnavirus is a genus of double-stranded RNA viruses. It is the only genus in the family Picobirnaviridae. Although amniotes, especially mammals, were thought to serve as hosts, it has been recently suggested that these viruses might infect bacteria and possibly some other invertebrates. If they do infect bacteria, then they are Bacteriophages. There are three species in this genus. Associated symptoms include gastroenteritis in animals and humans, though the disease association is unclear.

Plectrovirus is a genus of viruses, in the family Plectroviridae. Bacteria in the phylum Mycoplasmatota serve as natural hosts, making these viruses bacteriophages. Acholeplasma virus L51 is the only species in the genus.

<i>High Plains wheat mosaic emaravirus</i> Species of virus

High Plains wheat mosaic emaravirus (WMoV), or High Plains virus (HPV) or Maize red stripe virus (MRSV/MRStV) is the causative agent of High plains disease of maize and wheat. It is spread by wheat curl mite, Aceria tosichella, which also transmits Wheat streak mosaic virus. The mite's ability to transmit a number of different viruses to cereal crops make it an economically important agricultural pest. In late June 2017 this virus was first detected in Canada, in Alberta. The Alberta samples were 99% similar to those in the USA. As Wheat streak mosaic virus is already present in Alberta, and coinfection with these two causes even more severe damage, this could cause much higher yield losses.

<i>Emaravirus</i> Genus of viruses

Emaravirus is a genus of negative-strand RNA viruses which infect plants. The plant virus group is the sole genus in the family Fimoviridae. The genus has 21 species.

Lolavirus is a genus of viruses in the order Tymovirales, in the family Alphaflexiviridae. Plants, specifically ryegrass, serve as natural hosts. There is only one species in this genus: Lolium latent virus.

<span class="mw-page-title-main">Positive-strand RNA virus</span> Class of viruses in the Baltimore classification

Positive-strand RNA viruses are a group of related viruses that have positive-sense, single-stranded genomes made of ribonucleic acid. The positive-sense genome can act as messenger RNA (mRNA) and can be directly translated into viral proteins by the host cell's ribosomes. Positive-strand RNA viruses encode an RNA-dependent RNA polymerase (RdRp) which is used during replication of the genome to synthesize a negative-sense antigenome that is then used as a template to create a new positive-sense viral genome.

References

  1. ↑ Elbeaino, T; Digiaro, M; Martelli, GP (September 2009). "Complete nucleotide sequence of four RNA segments of fig mosaic virus". Archives of Virology. 154 (11): 1719–1727. doi:10.1007/s00705-009-0509-3. PMID   19777155. S2CID   898250.
  2. ↑ Elbeaino, T; Digiaro, M; Mielke-Ehret, N; Muehlbach, HP; Martelli, GP; Ictv Report, Consortium (November 2018). "ICTV Virus Taxonomy Profile: Fimoviridae". The Journal of General Virology. 99 (11): 1478–1479. doi: 10.1099/jgv.0.001143 . PMID   30204080. S2CID   52180832.
  3. 1 2 3 4 5 Ishikawa, K; Maejima, K; Komatsu, K (2013). "Fig mosaic emaravirus p4 protein is involved in cell-to-cell movement". Journal of General Virology. 94 (3): 682–686. doi: 10.1099/vir.0.047860-0 . PMID   23152372.
  4. 1 2 Ishikawa, K; Maejima, K; Nagashima, S (January 2012). "First report of fig mosaic virus infecting common fig (Ficus carica) in Japan". Journal of General Plant Pathology. 78 (2): 136–139. doi:10.1007/s10327-012-0359-9. S2CID   13946882.
  5. 1 2 3 4 Walia, JJ; Falk, BW (May 2012). "Fig mosaic virus mRNAs show generation by cap-snatching". Virology. 426 (2): 162–166. doi: 10.1016/j.virol.2012.01.035 . PMID   22356803.
  6. 1 2 3 4 5 Walia, JJ; Salem, NM; Falk, BM (January 2009). "Partial Sequence and Survey Analysis Identify a Multipartite, Negative-Sense RNA Virus Associated with Fig Mosaic". Plant Disease. 93 (1): 4–10. doi:10.1094/PDIS-93-1-0004. PMID   30764262.
  7. ↑ "ICTV Report: Fimoviridae".
  8. 1 2 Elbeaino, T; Digiaro, M; Alabdullah, A (May 2009). "A multipartite single-stranded negative-sense RNA virus is the putative agent of fig mosaic disease". Journal of General Virology. 90 (5): 1281–1288. doi: 10.1099/vir.0.008649-0 . PMID   19264612.
  9. 1 2 3 Ishikawa, K; Maejima, K; Komatsu, K (April 2012). "Identification and characterization of two novel genomic RNA segments of fig mosaic virus, RNA5 and RNA6". Journal of General Virology. 93 (7): 1612–1619. doi: 10.1099/vir.0.042663-0 . PMID   22513386.
  10. ↑ Lazarowitza, SG; Beachy, RN (April 1999). "Viral Movement Proteins as Probes for Intracellular and Intercellular Trafficking in Plants". The Plant Cell. 11 (4): 535–548. doi:10.1105/tpc.11.4.535. PMC   144200 . PMID   10213776.
  11. 1 2 3 Caglayan, K; Medina, V; Gazel, M (October 2009). "Putative agents of fig mosaic disease in Turkey". Turkish Journal of Agriculture & Forestry. 33: 469–476. doi: 10.3906/tar-0807-20 .
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.