Carnation Italian Ringspot Virus (CIRV) is a plant virus that impacts carnation plants (Dianthus caryophyllus). These flowers are a popular choice in ornamental flower arrangements. This article will provide an overview of CIRV. This will include the history of the virus, information on transmission, symptoms, and characteristics, and research about how it relates to plant physiology.
Carnation Italian ringspot virus | |
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Virus classification ![]() | |
(unranked): | Virus |
Realm: | Riboviria |
Kingdom: | Orthornavirae |
Phylum: | Kitrinoviricota |
Class: | Tolucaviricetes |
Order: | Tolivirales |
Family: | Tombusviridae |
Genus: | Tombusvirus |
Species: | Carnation Italian ringspot virus |
CIRV falls under the Tombusviridae family, known for its small, spherical virions and monopartite, positive-sense RNA genomes. Within this family, CIRV belongs to the Tombusvirus genus.
CIRV encodes five open reading frames (ORFs) that are transcribed within the host cells. The first of which is a 36-kDa protein that is involved in localization to the mitochondria for replication and is known as p36. The second ORF encodes a 95-kDa protein known as p95. This protein is the RNA dependent RNA polymerase. The third ORF encodes the coat protein, which is a 41-kDa protein known as p41. Finally, ORF four and five are nested and encode two proteins, one 22-kDa in size and the other 19-kDa in size (p22 and p19 respectively), that are involved in cell to cell movement of the virus and disease presentation. [2]
The virus enters the cell to cause infection and completes the life cycle in the cytoplasm. First, the virus experiences uncoating in the cytoplasm and transcription of early genes begins. Next, cytoplasmic viral factories are formed in order to replicate the viral mRNA. Because this is a positive sense RNA virus, the genomic RNA can be directly translated as mRNA by host ribosomes. Once proteins are made, the viral particles will assemble in the cytoplasm of the host cell. The virus encodes an RNA Dependent RNA Polymerase (RdRp) to replicate the RNA.
CIRV primarily spreads through mechanical means, including human handling and contaminated tools and equipment. When an infected plant is manipulated or pruned, the virus can be transferred to healthy plants, leading to new infections. This transmission mode emphasizes the importance of maintaining good sanitation practices in nurseries and greenhouses.
Apart from mechanical transmission, aphids can also transmit CIRV in a non-persistent manner. Aphids can acquire the virus from infected plants and transmit it to healthy plants, although their transmission capacity is temporary. Although less common, aphid-mediated transmission can contribute to the virus's dissemination. [3] The virus has been found to be resistant to a variety of treatment methods including temperature changes and UV radiation. [4]
CIRV infection in carnations results in symptoms that significantly impact the plants. Understanding these symptoms is essential for diagnosing and managing the disease effectively.
During infection, this virus can cause structural changes to the mitochondria of the host cells that it infects. This change is often represented by the formation of internal vesicles that are formed from the outer membrane of the mitochondria. These vesicles serve as replication centers to produce more viral RNA. This process is largely dependent on a protein known as p36, which is involved in the localization to the outer membrane of the mitochondria for the formation of these replication vesicles. [5]
This replication also depends on the use of host endosomal sorting complex required for transport (ESCRT). This complex is often used by viruses that need an envelope during infection, such as HIV. It has been characterized that other members of the Tombusviridae family utilize this complex, but recent research has suggested that CIRV also uses this system in its localization to the mitochondrial membrane for replication. This is done via protein-protein interactions and is distinct from other viruses in the family via these exact mechanisms. [6]
CIRV has not only been isolated in carnations. Reports out of Korea indicate that viral RNA was isolated using next generation sequencing (NGS) in Chrysanthemum zawadskii var. latilobum (CZ), also known as “Gujeolcho”. This plant serves as an herbal remedy and ornamental plant. After presenting disease symptoms similar to that of CIRV, researchers sequenced these plants and managed to isolate RNA that proved the cause. This was the first known isolation of CIRV in these plants and this research suggests that they could serve as a reservoir for the virus in this region. [7]
The virus has also been isolated from apple, pear and sour cherry in the German Democratic Republic. [8]
The study of the Carnation Italian Ringspot Virus (CIRV) has led to significant scientific advancements. This has contributed to our understanding of plant virology, vector-virus interactions, and the development of control strategies. This section explores critical areas of research and their impact.
One of the most significant advancements resulting from CIRV research is the development of molecular diagnostic techniques. These techniques allow for the rapid and accurate detection of CIRV in carnation plants. Molecular diagnostics are essential for early detection when symptoms are not readily visible.
The breeding and genetic modification of carnation varieties for resistance to CIRV have been significant achievements in CIRV research. The development of resistant varieties has been instrumental in mitigating the impact of the virus on carnation crops.
Research into the epidemiology of CIRV has provided valuable insights into how the virus spreads in plant populations. Understanding the dynamics of CIRV transmission has been critical for developing effective control measures.
Investigations into the biology and behavior of aphids, particularly in the context of CIRV transmission, have improved our knowledge of vector-host interactions.
In conclusion, research on CIRV has led to breakthroughs in molecular diagnostics, the development of resistant carnation varieties, the understanding of virus transmission dynamics, and insights into vector biology. These advancements have not only benefited the ornamental flower industry but have also contributed to broader knowledge in the fields of plant virology and plant pathology. CIRV serves as a valuable model system for studying plant viruses' biology and ecology, ultimately informing disease management strategies in various crops.
Carnation Italian Ringspot Virus (CIRV) holds a special place in plant pathology and virology, serving as a model system for studying various aspects of plant viruses and contributing to our broader understanding of these fields.
CIRV is an excellent model for studying the intricate interactions between plant viruses and their vectors, particularly aphids. The virus-vector relationship is crucial in the epidemiology of CIRV and other plant viruses. Understanding how aphids acquire and transmit CIRV has broader implications for vector-borne diseases in agriculture.
Researchers have gained insights into how plant viruses manipulate their insect vectors by investigating the behaviors and mechanisms underlying vector-mediated transmission. These interactions extend beyond CIRV to other viruses that rely on insects for transmission. This knowledge has paved the way for developing novel vector control strategies to disrupt the spread of viral diseases in crops.
As an RNA virus, CIRV has contributed to our understanding of the biology of such viruses. RNA viruses are a diverse group known for their rapid replication rates and mutation-prone genomes. CIRV's RNA-based genome has been a valuable model for studying key processes in RNA virus biology.
Research on CIRV has delved into the mechanisms of RNA replication, viral gene expression, and the role of viral RNA in host plant manipulation. These studies have provided insights into the fundamental processes underlying RNA virus infections, shedding light on the general biology of this virus group.
CIRV research has yielded valuable information about how plant viruses interact with their host plants. Understanding how viruses manipulate host plants to facilitate their infection and spread is a central aspect of plant-pathogen interactions.
The molecular and physiological changes induced by CIRV in carnation plants have provided insights into the mechanisms of virus-induced symptoms, such as ring-shaped lesions and mottling. These studies have broader applications in understanding how pathogens interact with their hosts, including manipulating cellular processes and defense mechanisms.
The strategies developed for managing CIRV have served as models for addressing similar challenges other plant viruses pose in various crops. The knowledge gained from CIRV research has informed disease management practices in agriculture and horticulture.
The use of resistant varieties, developed through CIRV research, has been adopted to combat other viral diseases in numerous crops. Breeding programs and genetic modification techniques inspired by CIRV studies have led to the development of plants with enhanced resistance to various pathogens.
In summary, CIRV's significance in plant pathology and virology extends beyond its impact on carnations. It is a valuable model for studying vector-virus interactions, RNA virus biology, host-plant interactions, and disease management strategies. The research on CIRV has contributed to the broader understanding of plant viruses, benefiting the agricultural and horticultural industries and advancing our knowledge of the fundamental processes underlying plant-pathogen interactions. [10]
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.
Brome mosaic virus (BMV) is a small, positive-stranded, icosahedral RNA plant virus belonging to the genus Bromovirus, family Bromoviridae, in the Alphavirus-like superfamily.
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Potyvirus is a genus of positive-strand RNA viruses in the family Potyviridae. Plants serve as natural hosts. Like begomoviruses, members of this genus may cause significant losses in agricultural, pastoral, horticultural, and ornamental crops. More than 200 species of aphids spread potyviruses, and most are from the subfamily Aphidinae. The genus contains 190 species and potyviruses account for about thirty percent of all currently known plant viruses.
A viroplasm, sometimes called "virus factory" or "virus inclusion", is an inclusion body in a cell where viral replication and assembly occurs. They may be thought of as viral factories in the cell. There are many viroplasms in one infected cell, where they appear dense to electron microscopy. Very little is understood about the mechanism of viroplasm formation.
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.
Cucumber mosaic virus (CMV) is a plant pathogenic virus in the family Bromoviridae. This virus has a worldwide distribution and a very wide host range, having the reputation of the widest host range of any known plant virus. It can be transmitted from plant to plant both mechanically by sap and by aphids in a stylet-borne fashion. It can also be transmitted in seeds and by the parasitic weeds, Cuscuta sp. (dodder).
Potato mop-top virus (PMTV) is a plant pathogenic virus transmitted through the vector Spongospora subterranea that affects potatoes. PMTV belongs to family of Virgaviridae, and the genus Pomovirus. The virus was first identified in 1966 by Calvert and Harrison in Britain, and is now reported in many other potato cultivating regions of the world including U.S.A., Canada, China, Pakistan, Japan, South American countries and many parts of Europe. Many disease management systems have been found to be ineffective against the virus, although a combination of sanitation and vector controls seems to work well.
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Orthotospovirus is a genus of negative-strand RNA viruses, in the family Tospoviridae of the order Bunyavirales, which infects plants. Tospoviruses take their name from the species Tomato spotted wilt orthotospovirus (TSWV) which was discovered in Australia in 1919. TSWV remained the only known member of the family until the early 1990s when genetic characterisation of plant viruses became more common. There are now at least twenty species in the genus with more being discovered on a regular basis. Member viruses infect over eight hundred plant species from 82 different families.
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.
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898, more than 11,000 of the millions of virus species have been described in detail. The study of viruses is known as virology, a subspeciality of microbiology.
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