Details of DPV and References
DPV NO: 13 June 1970
Species: Beet yellows virus | Acronym: BYV
There is a more recent description of this virus: DPV 377
Beet yellows virus
G. E. Russell Plant Breeding Institute, Trumpington, Cambridge, England
- Main Diseases
- Geographical Distribution
- Host Range and Symptomatology
- Transmission by Vectors
- Transmission through Seed
- Transmission by Grafting
- Transmission by Dodder
- Nucleic Acid Hybridization
- Stability in Sap
- Properties of Particles
- Particle Structure
- Particle Composition
- Properties of Infective Nucleic Acid
- Molecular Structure
- Genome Properties
- Relations with Cells and Tissues
- Ecology and Control
Watson (1942) and
Virus de la jaunisse de la betterave (Rev. appl. Mycol. 15: 548)
- Beta virus 4 (Rev. appl. Mycol. 36: 308)
- Corium betae (Rev. appl. Mycol. 19: 229)
- Beta virus 4 (Rev. appl. Mycol. 36: 308)
A virus with flexuous filamentous particles c. 1250 nm long. Transmitted by many species of aphid in the semi-persistent manner but by sap inoculation only with difficulty. Host range moderate, mainly in the Chenopodiaceae. Widely distributed throughout the beet-growing areas of the world.
Causes a yellows disease in Beta vulgaris (sugar beet, red beet, spinach beet, etc.) and in Spinacia oleracea (spinach).
World-wide in major sugar beet growing areas.
Host Range and Symptomatology
Host range is moderate, mainly in the Chenopodiaceae; species in at least ten dicotyledonous families have been infected experimentally (Bennett, 1960). Transmitted readily by aphid inoculation, with difficulty by manual inoculation of sap, for example to the following species:
- Beta vulgaris(sugar beet). Young leaves of glasshouse plants often show vein-clearing and vein-etch (Fig. 1). Older leaves of field and glasshouse beet become yellow, thickened and brittle and usually have numerous small red or brown necrotic spots (Fig. 2).
Chenopodium foliosum or C. capitatum. Acute stunting, distortion and
vein-clearing in young leaves
and usually premature death.
- Claytonia perfoliata. Plants inoculated by aphids show systemic red spots and chlorosis in older leaves (Fig. 4). Manually inoculated plants develop red necrotic lesions in inoculated leaves but do not become infected systemically (Russell, 1963).
- Sugar beet, Claytonia perfoliata or Tetragonia expansa are suitable for maintaining cultures.
- Claytonia perfoliatais a good host for sap inoculation tests and also for testing aphids.
- Sugar beet and Chenopodium foliosum are satisfactory alternatives although in these the virus may become systemic even after sap inoculation.
Many minor variants have been isolated from local lesions, producing symptoms in sugar beet ranging from very mild yellowing to very severe vein-etch and leaf necrosis. All are apparently serologically related and there is usually complete cross-protection between them (Russell, 1964), Bennett (1960), however, described some strains which do not cross protect.
Transmission by Vectors
Transmissible by more than 22 species of aphids (Kennedy, Day & Eastop, 1962) but Myzus persicae and Aphis fabae are the principal vectors in the field. All instars transmit but adults are the most efficient. Transmission is of the semi-persistent type (Watson, 1946; Sylvester, 1956), the virus being retained by the vector for up to 3 days, with a half-life of about 8 hr. For optimum transmission, acquisition feeds of more than 12 hr and test feeds of at least 6 hr are necessary. Probably no latent period. Not transmitted to progeny of vectors. Vectors do not retain virus after moulting (Watson, 1960).
Transmission through Seed
Early reports of seed transmission have not been confirmed.
Transmission by Dodder
Several species can transmit (Fuchs & Beiss, 1954). Aphids can acquire virus from some non-transmitting species of dodder growing on infected plants (Bennett, 1960).
The virus is weakly immunogenic. Antisera may be prepared by intravenous, intramuscular or intraperitoneal injections of clarified sap from infected plants; sap from Claytonia perfoliata is particularly suitable. Tube-precipitin or slide-agglutination tests, using clarified sap, are satisfactory for routine diagnosis and crude quantitative assays.
No evidence of serological relationship to any other virus (Brandes & Bercks, 1965). Resembles citrus tristeza, festuca necrosis, apple chlorotic leaf spot, apple stem-pitting and citrus tatter-leaf viruses in several features, particularly particle morphology, symptomatology and difficulty of sap inoculation (Gibbs, 1969).
Stability in Sap
Thermal inactivation point (10 min) in sap is about 55°C; dilution end point is up to 10-4 depending on host plant used. Infectivity is retained in frozen sap for more than a year but rarely for more than 1 day at 20°C.
The virus is very unstable. Partial purification from clarified sap has been achieved by differential centrifugation. The virus forms a single light-scattering zone when centrifuged in sucrose density gradients (Mundry, 1958).
Properties of Particles
Flexuous filamentous particles about 1250 nm long and 10 nm in diameter with sub-units arranged around a hollow core (Horne, Russell & Trim, 1959) in a helix of pitch between 3.0 and 3.4 nm (Varma, Gibbs, Woods & Finch, 1968). Good contrast achieved by mixing 2% phosphotungstate with virus in clarified sap (Fig. 5).
Relations with Cells and Tissues
Particularly associated with degeneration of phloem tissues. Arrays of virus particles have been found in chloroplasts (Cronshaw, Hoefert & Esau, 1966).
Beet yellows virus often occurs in beet together with beet mild yellowing or beet western yellows viruses, which, however, are transmitted by aphids in the persistent manner. They also differ from beet yellows virus in symptomatology, host range, particle morphology and in serological tests (Russell, 1968; Duffus, 1964; Gold & Duffus, 1967).
Photographs: courtesy of Plant Breeding Institute, Cambridge; Fig. 5 courtesy of Rothamsted Experimental Station.
Mature leaf of field-infected sugar beet, showing chlorosis and necrotic spots which are usually more numerous near the leaf tip. Such leaves are invariably thickened and brittle.
Chenopodium foliosum seedlings: (left) virus-free, (right) infected, showing vein-clearing and distortion in young leaves.
References list for DPV: Beet yellows virus (13)
- Bennett, Tech. Bull. U.S. Dep. Agric. 1218, 63 pp., 1960.
- Brandes & Bercks, Adv. Virus Res. 11: 1, 1965.
- Cronshaw, Hoefert & Esau, J. Cell Biol. 31: 429, 1966.
- Duffus, Phytopathology 54: 736, 1964.
- Fuchs & Beiss, Naturwissenschaften 41: 506, 1954.
- Gibbs, Adv. Virus Res. 14: 288, 1969.
- Gold & Duffus, Virology 31: 308, 1967.
- Horne, Russell & Trim, J. molec. Biol. 1: 234, 1959.
- Hull, Bull. Minist. Agric. Fish. Fd Lond. 142, 53 pp., 1950.
- Kennedy, Day & Eastop, A conspectus of aphids as vectors of plant viruses,London, Commonwealth Institute of Entomology, 1962.
- Mundry, Z. Naturf. Ser. B. 13: 19, 1958.
- Roland, Sucr. belge 55: 213, 1936.
- Russell, Nature, Lond. 197: 623, 1963.
- Russell, Ann. appl. Biol. 53: 377, 1964.
- Russell, Br. Sug. Beet Rev. 37: 77, 1968.
- Sylvester, J. Am. Soc. Sug. Beet Technol. 9: 56, 1956.
- Varma, Gibbs, Woods & Finch, J. gen. Virol. 2: 107, 1968.
- Watson, Ann. appl. Biol. 29: 358, 1942.
- Watson, Proc. R. Soc. B, 133: 200, 1946.
- Watson, Rep. 7th Commonwealth Entom. Conf. London: 157, 1960.