Orchid fleck dichorhavirus

Last updated
Orchid fleck dichorhavirus
Virus classification Red Pencil Icon.png
(unranked): Virus
Realm: Riboviria
Kingdom: Orthornavirae
Phylum: Negarnaviricota
Class: Monjiviricetes
Order: Mononegavirales
Family: Rhabdoviridae
Genus: Dichorhavirus
Species:
Orchid fleck dichorhavirus
Synonyms

Orchid fleck virus

Orchid fleck dichorhavirus, commonly called Orchid fleck virus (OFV), is a non-enveloped, segmented, single-stranded (ss) RNA negative-strand virus, transmitted by the false spider mite, Brevipalpus californicus. OFV causes necrotic and chlorotic lesions on the leaves [1] of many genera in the family Orchidaceae.

Contents

Introduction

Orchid fleck virus, despite its presence worldwide, only affects a small spectrum of human life. Orchids are not used for food but rather serve mainly as ornamental decoration. Therefore, only about 2 to 3 scientific reports are written about OFV each year. The whole genome of OFV has been sequenced and its six main protein products have been sequenced as well. [2]

Much is still not known about OFV including how exactly and why vector mites travel from orchid to orchid, and more host species of flowers are being discovered annually. The more information researchers discover, the more they realize there is still much left to learn. Many orchid enthusiasts are participating in "citizen science" by posting their OFV-related findings on international horticulture blogs and forums.[ citation needed ]

Virion morphology

OFV was first described as bacilliform [3] but depending on the method of preparation, OFV can appear bullet-shaped or bacilliform. On average, OFV is 40 nm in diameter and between 100 and 150 nm long. Each viral particles is organized into a tight 25 turn helix, with a pitch of about 4.5 nm. [4]

Genomics

OFV contains two ssRNA molecules, RNA1 and RNA2, of 6413 and 6001 base pairs, respectively. GenBank contains the whole sequenced genome of OFV. RNA1 (GenBank AB244417) codes for five proteins whereas RNA2 (GenBank AB244418) only codes for one. [2] Both strands possess open reading frames (ORF), which are read in the negative sense.

RNA1

RNA2

Pathophysiology

Chlorotic and necrotic flecks, spots, and/or ringspots, as well as yellow flecks or spots are all symptoms of an OFV infection. Studies have also shown that OFV may prevent the propagation of other viruses in an already OFV-infected plant. [5]

Vector

The false spider mite, B. californicus serves as the major vector for OFV. [6] Brevipalpus mites go through four distinct, active life stages, each separated by nonmotile chrysalis stages. [7] The protonymph, deutonymph, and adult stages can infect their host plants with OFV, whereas the larval stage is not infectious. [5] Even after three weeks of incubation of an OFV-positive mite on an OFV-resistant plant, B. californicus proved to still be infectious, showing that OFV is persistent. [8]

Hosts

OFV is able to naturally infect around 50 different species in 31 genera, all belonging to the family Orchidaceae. 25 other species from 11 non-orchid families have been infected through sap transmission or artificial viral inoculation. [5]

Life cycle

Studies have not shown whether or not OFV actually replicates within B. californicus [8] but electron microscopy has revealed an intricate viral life cycle within the host cells.

Viral ssRNA is replicated and transcribed into mRNA in the host cell's nucleus. Viral mRNA is then exported out of the nucleus into the cytoplasm where it is translated into viral protein by the host's ribosomes. The viral proteins then reenter the nucleus where they aggregate into a viroplasm. There, the various viral structural proteins assemble with both strands of ssRNA to form complete OFV particles. These particles often cluster in between the inner and outer nuclear membranes, causing visible projections which often evaginate into cytoplasmic vesicles. Electron microscopy has revealed clusters of viral particles positioned perpendicular to the inner nuclear membrane, the endoplasmic reticulum, as well as the aforementioned cytoplasmic vesicles, forming distinctive “spoked wheel” structures. [5]

Effects on fitness

Infected orchids don't bloom as well as healthy ones, affecting efficacy of pollination and fertilization. Also, the orchids that do bloom look lifeless making them less attractive on the cut flower market. [5]

Epidemiology

Cases of orchid fleck virus or OF-like viruses have been reported in Australia, Brazil, China, Columbia, Costa Rica, Denmark, Germany, Japan, Korea, South Africa, and the United States, i.e. every continent except for Antarctica. [5]

Due to the fact that viruses depend on their host cell for replication, OFV cannot be cultured independently. However, two non-orchid indicator hosts (plants used in research that show characteristic symptoms of specific viral infections) C. quinoa and T. expansa are commonly used for viral inoculation and isolation. [5]

There are no known pathogens of OFV itself but its vector, B. californicus has a symbiotic relationship with bacteria of the genus Cardinium. The symbiont is the cause of the mites' thelytokous method of reproduction (where females are produced from unfertilized eggs) and the explanation for the absence of male B. californicus mites. [9]

Diagnosis

Thin tissue samples from plants with visible symptoms of OFV can undergo: [5]

Prevention

Methods for preventing the spread of OFV among separate plants: [10]

Treatment

Once a plant is infected with OFV, it is unclear whether pruning visibly infected tissue will cure the plant of the virus. It is also unclear whether infected plants produce seeds containing viral particles.[ citation needed ]

History

The earliest recorded work concerning Orchid Fleck Virus was published in Japan in 1969. OFV was reported as concentrations of short, rod-like particles in chlorotic lesions on the leaves of boat orchids of the genus Cymbidium . [3]

Human relevance

Orchids and other tropical flowers are extremely important to the agricultural economy of many Southeast Asian countries. The Vanda 'Miss Joaquim' orchid hybrid is Singapore's national flower. According to the Orchid Society, the world market for orchids is worth more than $1 billion with Japan and the United States leading the way in 2010. [11] In the US in 2005 produced around $144 million worth of orchids. [12]

Related Research Articles

<i>Paramyxoviridae</i> Family of viruses

Paramyxoviridae is a family of negative-strand RNA viruses in the order Mononegavirales. Vertebrates serve as natural hosts. Diseases associated with this family include measles, mumps, and respiratory tract infections. The family has four subfamilies, 17 genera, and 78 species, three genera of which are unassigned to a subfamily.

<i>Rhabdoviridae</i> Family of viruses in the order Mononegavirales

Rhabdoviridae is a family of negative-strand RNA viruses in the order Mononegavirales. Vertebrates, invertebrates, plants, fungi and protozoans serve as natural hosts. Diseases associated with member viruses include rabies encephalitis caused by the rabies virus, and flu-like symptoms in humans caused by vesiculoviruses. The name is derived from Ancient Greek rhabdos, meaning rod, referring to the shape of the viral particles. The family has 40 genera, most assigned to three subfamilies.

<i>Hepadnaviridae</i> Family of viruses

Hepadnaviridae is a family of viruses. Humans, apes, and birds serve as natural hosts. There are currently 18 species in this family, divided among 5 genera. Its best-known member is hepatitis B virus. Diseases associated with this family include: liver infections, such as hepatitis, hepatocellular carcinomas, and cirrhosis. It is the sole accepted family in the order Blubervirales.

Caulimoviridae is a family of viruses infecting plants. There are 94 species in this family, assigned to 11 genera. Viruses belonging to the family Caulimoviridae are termed double-stranded DNA (dsDNA) reverse-transcribing viruses i.e. viruses that contain a reverse transcription stage in their replication cycle. This family contains all plant viruses with a dsDNA genome that have a reverse transcribing phase in their lifecycle.

<i>Potyviridae</i> Family of viruses

Potyviridae is a family of positive-strand RNA viruses that encompasses more than 30% of known plant viruses, many of which are of great agricultural significance. The family has 12 genera and 235 species, three of which are unassigned to a genus.

<span class="mw-page-title-main">Viral replication</span> Formation of biological viruses during the infection process

Viral replication is the formation of biological viruses during the infection process in the target host cells. Viruses must first get into the cell before viral replication can occur. Through the generation of abundant copies of its genome and packaging these copies, the virus continues infecting new hosts. Replication between viruses is greatly varied and depends on the type of genes involved in them. Most DNA viruses assemble in the nucleus while most RNA viruses develop solely in cytoplasm.

<i>Cowpea chlorotic mottle virus</i> Species of virus

Cowpea chlorotic mottle virus, known by the abbreviation CCMV, is a virus that specifically infects the cowpea plant, or black-eyed pea. The leaves of infected plants develop yellow spots, hence the name "chlorotic". Similar to its "brother" virus, Cowpea mosaic virus (CPMV), CCMV is produced in high yield in plants. In the natural host, viral particles can be produced at 1–2 mg per gram of infected leaf tissue. Belonging to the bromovirus genus, cowpea chlorotic mottle virus (CCMV) is a small spherical plant virus. Other members of this genus include the brome mosaic virus (BMV) and the broad bean mottle virus (BBMV).

<i>Alfalfa mosaic virus</i> Species of virus

Alfalfa mosaic virus (AMV), also known as Lucerne mosaic virus or Potato calico virus, is a worldwide distributed phytopathogen that can lead to necrosis and yellow mosaics on a large variety of plant species, including commercially important crops. It is the only Alfamovirus of the family Bromoviridae. In 1931 Weimer J.L. was the first to report AMV in alfalfa. Transmission of the virus occurs mainly by some aphids, by seeds or by pollen to the seed.

Rice hoja blanca tenuivirus (RHBV), meaning "white leaf rice virus", is a plant virus in the family Phenuiviridae. RHBV causes Hoja blanca disease (HBD), which affects the leaves of the rice plant Oryza sativa, stunting the growth of the plant or killing it altogether. RHBV is carried by an insect vector, Tagosodes orizicolus, a type of planthopper. The virus is found in South America, Mexico, throughout Central America, the Caribbean region, and the southern United States. In South America, the disease is endemic to Colombia, Venezuela, Ecuador, Peru, Suriname, French Guiana and Guyana.

<i>Cymbidium mosaic virus</i> Species of virus

Cymbidium mosaic virus (CymMV) is a plant pathogenic virus of the family Alphaflexiviridae.

Strawberry crinkle cytorhabdovirus, commonly called Strawberry crinkle virus (SCV), is a negative sense single stranded RNA virus that threatens strawberry production worldwide. This virus reduces plant rigidity, runner production, fruit size, and production, while causing distortion and crinkling of the leaves. This virus was first described in 1932 in Oregon and California with commercial strawberry varieties, and later became an issue around the world, including North America, South America, Europe, South Africa, New Zealand, Australia, and Japan. Of the family Rhabdoviridae, it is a large family of viruses that affects plants, vertebrates, and invertebrates. Specifically, this virus infects strawberry plants of the genus Fragaria and is transmitted through two aphid vectors that feed on strawberries, Chaetosiphon fragaefolii and C. jacobi. When SCV is combined with other aphid-transmitted strawberry viruses, such as mottle, mild yellow-edge, vein banding, or pallidosis, the damage becomes even more deleterious. Economically, the only significant host of SCV is Fragaria ananassa.

<i>Carlavirus</i> Genus of viruses

Carlavirus, formerly known as the "Carnation latent virus group", is a genus of viruses in the order Tymovirales, in the family Betaflexiviridae. Plants serve as natural hosts. There are 53 species in this genus. Diseases associated with this genus include: mosaic and ringspot symptoms.

Cilevirus is a genus of viruses in the family Kitaviridae. Plants serve as natural hosts. There are two species: Citrus leprosis virus C and Citrus leprosis virus C2.

Dichorhavirus is a genus of negative sense, single-stranded RNA viruses of plants within the family Rhabdoviridae. Dichorhaviruses have segmented genomes and their short bacilliform virions are not enveloped. Dichorhaviruses are transmitted by mites.

<i>Fig mosaic emaravirus</i> Species of 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. It is a member of the genus Emaravirus and order Bunyavirales and is transmitted mainly by the eriophyid mite Aceria ficus. 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.

Citrus leprosis(CL) is an economically important viral disease affecting citrus crops. This emerging disease is widely distributed in South and Central America, from Argentina to Mexico. The disease is associated with up to three different non-systemic viruses, which cause similar symptoms in the citrus hosts and are transmitted by the same vector, mites of the genus Brevipalpus; although they have vastly different genomes. Citrus leprosis virus nuclear type (CiLV-N) is found in the nuclei and cytoplasm of infected cells, while Citrus leprosis virus cytoplasmic type (CiLV-C) is found in the endoplasmic reticulum. In 2012, a new virus causing similar symptoms was found in Colombia and it was named Citrus leprosis virus cytoplasmic type 2 (CiLV-C2) due to its close similarity to CiLV-C. The cytoplasmic type viruses are the most prevalent and widely distributed of the three species.

Lily virus X (LVX) is a pathogenic ssRNA(+) plant virus of the family Alphaflexiviridae and the order Tymovirales.

<i>Avian metaavulavirus 2</i> Species of virus

Avian metaavulavirus 2, formerly Avian paramyxovirus 2, is a species of virus belonging to the family Paramyxoviridae and genus Metaavulavirus. The virus is a negative strand RNA virus containing a monopartite genome. Avian metaavulavirus 2 is one of nine species belonging to the genus Metaavulavirus. The most common serotype of Avulavirinae is serotype 1, the cause of Newcastle disease (ND). Avian metaavulavirus 2 has been known to cause disease, specifically mild respiratory infections in domestic poultry, including turkeys and chickens, and has many economic effects on egg production and poultry industries. The virus was first isolated from a strain in Yucaipa, California in 1956. Since then, other isolates of the virus have been isolated worldwide.

<i>Botourmiaviridae</i> Family of viruses

Botourmiaviridae is a family of positive-strand RNA viruses which infect plants and fungi. The family includes four genera: Ourmiavirus, Botoulivirus, Magoulivirus and Scleroulivirus. Members of genus Ourmiavirus infect plants and the other genera infect fungi. The member viruses have genomes which range from 2900 to 4800 nucleotides.

References

  1. ↑ (Image) Kubo KS, Freitas-Astu´a J, Machado MA, Kitajima EW 2009. Orchid fleck symptoms may be caused naturally by two different viruses transmitted by Brevipalpus. J Gen Plant Pathol 75:250–255.
  2. 1 2 Kondo H, Maeda T, Shirako Y, Tamada T 2006. Orchid fleck virus is a rhabdovirus with an unusual bipartite genome. J Gen Virol 87:2413–2421.
  3. 1 2 Doi Y, Arai K, Yora K 1969. Distribution of bacilliform virus particles in Masaki mosaic disease and Cymbidium ring spot disease. Ann Phytopathol Soc Jpn 35:388.
  4. ↑ Kondo H, Maeda T, Tamada T 2009. Identification and characterization of structural proteins of orchid fleck virus. Arch Virol 154:37–45.
  5. 1 2 3 4 5 6 7 8 Peng DW, Zheng GH, Zheng ZZ, Tong QX, Ming YL 2013 Orchid fleck virus: an unclassified bipartite, negative-sense RNA plant virus. Archives of Virology.158(2):313-323.
  6. ↑ Maeda T, Kondo H, Mitsuhata K, Tamada T 1998. Evidence that orchid fleck virus is efficiently transmitted in a persistent manner by the mite Brevipalpus californicus. Archived 2017-12-01 at the Wayback Machine In: Proceedings of the 7th Int Cong Plant Pathol, pp 13–18.
  7. ↑ Childers CC, Rodrigues JCV 2011. An overview of Brevipalpus mites (Acari: Tenuipalpidae) and the plant viruses they transmit Zoosymposia 6:168–180.
  8. 1 2 Kondo H, Maeda T. & Tamada T 2003. Orchid fleck virus:Brevipalpus californicus mite transmission, biological properties and genome structure. Exp Appl Acarol 30, 215–223. doi : 10.1023/B:APPA.0000006550.88615.10
  9. ↑ Groot TVM & Breeuwer JAJ 2006. Cardinium symbionts induce haploid thelytoky in most clones of three closely related Brevipalpusspecies. Experimental and Applied Acarology, 39, 257–271.
  10. ↑ Liu L, Lin ZK, Guo Y 2010. Progress on molecule biology of phalaenopsis virus and the corresponding prevention measures. Anhui Agric Sci Bull 16(21–23):126.
  11. ↑ "Orchid Market Passed $1 Billion Mark". Orchid Society. Orchid Society. 10 June 2011. Retrieved 17 September 2020.
  12. ↑ U.S. Department of Agriculture. 2006a. Floriculture crops 2005 summary. Agricultural Statistics Board, Washington D.C.
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.