Indian citrus ringspot virus
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Distribution Table
- Risk of Introduction
- Hosts/Species Affected
- Host Plants and Other Plants Affected
- Growth Stages
- List of Symptoms/Signs
- Biology and Ecology
- Means of Movement and Dispersal
- Detection and Inspection
- Similarities to Other Species/Conditions
- Prevention and Control
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Indian citrus ringspot virus
Other Scientific Names
- Citrus ring spot virus
- Citrus ringspot virus
- Indian citrus ring spot virus
Taxonomic TreeTop of page
- Domain: Virus
- Unknown: "Positive sense ssRNA viruses"
- Unknown: "RNA viruses"
- Order: Tymovirales
- Family: Alphaflexiviridae
- Genus: Mandarivirus
- Species: Indian citrus ringspot virus
Notes on Taxonomy and NomenclatureTop of page Indian citrus ringspot virus (ICRSV), which is now recognized as a distinct virus (Rustici et al., 2000, 2002), was initially known in India as Citrus ringspot virus (e.g. Byadgi et al., 1993; Thind et al., 1995; Ahlawat, 1997a, b; Lokhande, 1997; Pant and Ahlawat, 1998). Its name was changed to Indian citrus ringspot virus to avoid confusion with Citrus ringspot virus: a strain of Citrus psorosis virus, which has long been known to occur worldwide and is the type species of the Ophiovirus genus (Milne et al., 2000; Vaira et al., 2004). Although ICRSV has some similarities to potex-, fovea-, carla- and allexiviruses, it is distinct from such viruses (Rustici et al., 2000, 2002) and is now recognized as the type species of the newly recognised Mandarivirus genus (Rustici et al., 2000, 2002), which is now included in the Flexiviridae family (Adams et al., 2004).
DescriptionTop of page The virus has particles measuring approximately 650 x 15 nm with clearly visible cross banding (Rustici et al., 2000). The particles contain a coat protein of 34 kDa and single-stranded RNA of 7560 nucleotides. The genomic RNA contains six open-reading frames (ORFs) which encode putative proteins of 187.3, 25, 12, 6.4, 34 and 23 kDa, respectively (Rustici et al., 2000, 2002). ORF 1 probably encodes the viral replicase; ORFs 2, 3 and 4 form the triple-gene block; ORF 5 encodes the capsid protein; and the function of ORF 6 is unknown.
In thin sections of leaves, particles occur in the cytoplasm of parenchyma cells (Rustici et al., 2000).
DistributionTop of page
The virus is widespread (10-100% incidence) wherever it occurs in India (e.g. Pant and Ahlawat, 1998), the only country in which it is known to occur.
See also CABI/EPPO (1998, No. 308).
Distribution TableTop of page
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|India||Widespread||Ahlawat, 1997a; Ahlawat, 1997b; Pant and Ahlawat, 1998; CABI/EPPO, 2015|
|-Andhra Pradesh||Widespread||Pant and Ahlawat, 1998; CABI/EPPO, 2015|
|-Haryana||Widespread||Pant and Ahlawat, 1998; CABI/EPPO, 2015|
|-Indian Punjab||Widespread||Thind et al., 1995; Thind and Arora, 1997; Lore and Cheema, 2001; Lore et al., 2001; CABI/EPPO, 2015|
|-Karnataka||Widespread||Pant and Ahlawat, 1998; CABI/EPPO, 2015|
|-Maharashtra||Widespread||Lokhande, 1997; CABI/EPPO, 2015|
|-Rajasthan||Widespread||Pant and Ahlawat, 1998; CABI/EPPO, 2015|
|-Uttar Pradesh||Widespread||Pant and Ahlawat, 1998; CABI/EPPO, 2015|
|Pakistan||Absent, reported but not confirmed||CABI/EPPO, 2015|
Risk of IntroductionTop of page ICRSV has been reported to occur only in India. It is recommended that only virus-free material should be exchanged in internal and external trade.
Hosts/Species AffectedTop of page Experimental Hosts
ICRSV is graft-transmissible to its natural hosts and to citron (Citrus medica) and rough lemon (Citrus jambhiri). The virus is also mechanically transmissible to five herbaceous species. It induces local lesions in Chenopodium amaranticolor [Chenopodium giganteum], Chenopodium quinoa, Glycine max, and Vigna unguiculata, and systemic infection in Phaseolus vulgaris cv. Saxa, which is a good source of virus for purification (Rustici et al., 2000).
Host Plants and Other Plants AffectedTop of page
|Citrus nobilis x Citrus deliciosa (Kinnow mandarin)||Rutaceae||Main|
|Citrus reshni (Cleopatra mandarin)||Rutaceae||Main|
|Citrus sinensis (navel orange)||Rutaceae||Main|
Growth StagesTop of page Flowering stage, Fruiting stage, Vegetative growing stage
SymptomsTop of page In naturally infected mandarin (Citrus spp.) and sweet orange (Citrus sinensis) trees, ICRSV induces the development in leaves of one to several conspicuous chlorotic rings. Severely affected trees suffer a significant loss of fruit yield and later decline with dieback symptoms.
List of Symptoms/SignsTop of page
|Leaves / abnormal colours|
|Whole plant / plant dead; dieback|
Biology and EcologyTop of page The only known source of infection is infected citrus plants. The virus has no known vectors or known mode of natural spread; its widespread occurrence in India is probably partly due to past inadvertent use of infected scion budwood when producing young trees for replanting or establishing orchards.
Means of Movement and DispersalTop of page The virus is transmitted by grafting, but is not seedborne or soilborne and has no known vector (Pant and Ahlawat, 1998; Thind et al., 1999). It has, however, been detected in pollen (Pant and Ahlawat, 1998).
ImpactTop of page Infection by ICRSV reduced the number and weight of fruits of Kinnow mandarin (Citrus nobilis x Citrus deliciosa) plants by 45 and 55%, respectively. Fruit length, breadth, weight, granulation index and juice content were reduced by 11.59, 13.75, 38.88, 22.00 and 15.25%, respectively, whereas the shape index, peel, rag and peel thickness were increased, respectively, by 2.32, 10.23, 32.41 and 50%. Infected fruits had reduced levels of total soluble solids (12.96%), ascorbic acid (9.09%) and reducing sugars (10.90%), but an increased acidity of 56.69% (Lore et al., 2001). Similar effects of infection have also been reported by Thind et al. (1998).
DiagnosisTop of page
ICRSV induces ringspot leaf symptoms in graft-inoculated plants of Kinnow mandarin (Citrus nobilis x Citrus deliciosa), Cleopatra mandarin (Citrus reshni), citron (Citrus medica) and rough lemon (Citrus jambhiri). Symptoms, however, are more conspicuous and appear sooner (usually 90 days or so after graft-infection) in Kinnow and Cleopatra mandarins which are, therefore, recommended as indicator hosts (Thind et al., 1999).
Reverse transcription-polymerase chain reaction (RT-PCR) has also been used experimentally for the detection of ICRSV (Shelley et al., 2003). For further information on molecular diagnostics for the detection of viruses and virus-like pathogens in citrus, see Rao et al. (2008).
Detection and InspectionTop of page Because ICRSV can occur in complex with other viruses, it is not possible to identify the virus with certainty by symptoms induced in Citrus spp. Specific identification requires the use of one or more of the diagnostic procedures outlined in the 'Diagnosis' section of this datasheet.
Similarities to Other Species/ConditionsTop of page The virus is the type (and only) species of the newly recognised Mandarivirus genus (Vaira et al., 2004). ICRSV has some similarities to potex-, carla-, fovea- and allexiviruses (Rustici et al., 2000), but phylogenetic analysis suggests that it differs significantly from these viruses (Rustici et al., 2002).
Prevention and ControlTop of page
ICRSV can be managed by an integrated approach using virus-free planting material, sanitation, cultural practices and regulatory measures.
The virus was eliminated from infected bud-sticks of Kinnow mandarin (Citrus nobilis x Citrus deliciosa) by exposure to dry heat for 30 minutes or more at 50°C or for 120 minutes at 45°C (Cheema et al., 1999). The production, multiplication and distribution of virus-free plants so produced are recommended for the effective and efficient control of ICRSV (Thind et al., 1999; Hoa et al., 2004; Singh et al., 2006; Sharma et al., 2007, 2008).
ReferencesTop of page
Adams MJ; Antoniw JF; Bar-Joseph M; Brunt AA; Candresse T; Foster GD; Martelli GP; Milne RG; Zavriev SK; Fauquet CM, 2004. The new plant virus family Flexiviridae and assessment of molecular criteria for species demarcation. Archives of Virology, 149:1045-1060.
Ahlawat YS; Pant RP, 2008. Indian citrus ringspot virus. In: Characterization, diagnosis & management of plant viruses. Volume 2: horticultural crops [ed. by Rao GP, Myrta A, Ling KS] Houston, USA: Studium Press LLC, 97-107.
Baranwal VK; Ahlawat YS, 2008. Molecular diagnostics for detection of virus and virus-like pathogens in citrus. In: Techniques in diagnosis of plant viruses [ed. by Rao GP, Valverde RA, Dovas CI] Houston, USA: Studium Press LLC, 141-151.
Byadgi AS; Ahlawat YS; Chakraborty NK; Varma A; Srivastava M; Milne RG, 1993. Characterization of a filamentous virus associated with citrus ringspot in India. In: Moreno P et al., ed. Proceedings of the 12th Conference of the International Organization of Citrus Virologists. Riverside, California, USA, 155-162.
Milne RG; Garcia ML; Grau O, 2000. Genus Ophiovirus. In: van Regenmortel MHV et al., eds. Virus Taxonomy; Seventh Report of the International Committee on Taxonomy of Viruses. USA: Academic Press, San Diego, 627-631.
Roy A; Fayad A; Barthe G; Brlansky RH, 2005. A multiplex polymerase chain reaction method for reliable, sensitive and simultaneous detection of multiple viruses in citrus trees. Journal of Virological Methods, 129(1):47-55. http://www.sciencedirect.com/science/journal01660934
Rustici G; Accotto GP; Noris E; Masenga V; Luisoni E; Milne RG, 2000. Indian citrus ringspot virus: a proposed new species with some affinities to potex-, carla-, fovea- and allexiviruses. Archives of Virology, 145(9):1895-1908.
Sanjeev Sharma; Balwinder Singh; Gita Rani; Zaidi AA; Hallan V; Avinash Nagpal; Virk GS, 2007. In vitro production of Indian citrus ringspot virus (ICRSV) free kinnow plants employing phytotherapy coupled with shoot tip grafting. In Vitro Cellular & Developmental Biology - Plant, 43(3):254-259. http://www.ingenta.com/journals/browse/cabi/ivp
Sanjeev Sharma; Balwinder Singh; Gita Rani; Zaidi AA; Hallan VK; Nagpal AK; Virk GS, 2008. In vitro production of Indian citrus ringspot virus (ICRSV) free Kinnow plants employing thermotherapy coupled with shoot tip grafting. Plant Cell, Tissue and Organ Culture, 92(1):85-92. http://springerlink.metapress.com/openurl.asp?genre=journal&issn=0167-6857
Sanjeev Sharma; Balwinder Singh; Gita Rani; Zaidi AA; Vipin Hallan; Avinash Nagpal; Virk GS, 2007. Production of Indian citrus ringspot virus free plants of Kinnow employing chemotherapy coupled with shoot tip grafting. Journal of Central European Agriculture, 8(1):1-8. http://www.agr.hr/jcea/issues/jcea8-1/pdf/jcea81-1.pdf
Shelley P; Barthe GA; Derrick KS; Ahlawat YS, 2003. Comparison of isolates of Indian citrus ringspot virus and Citrus psorosis virus. Indian Phytopathology, 56(2):230-232.
Singh B; Sharma S; Rani G; Zaidi AA; Hallan V; Virk GS; Nagpal A, 2006. In vitro production of Indian citrus ringspot virus-free plants of Kinnow mandarin (Citrus nobilis Lour × C. deliciosa Tenora) by nucellar embryo culture. Plant Pathology Journal (Faisalabad), 5(3):274-282. http://www.ansinet.org/ppj
Vaira AM; Accotto GP; Gago-Zachert S; Garcia ML; Grau O; Milne RG; Morikawa T; Natsuaki T; Torok V; Verbeek M; Vetten HJ, 2004. Genus Ophiovirus. In: Fauquet CM, Mayo MA, Maniloff J, Desselberger U, Ball LA, eds. Virus Taxonomy, VIIIth Report of the ICTV. London, UK: Elsevier/Academic Press, 681-693.
Distribution MapsTop of page
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