![]() 236 July 1981 | Family: Bromoviridae Genus: Bromovirus Species: Melandrium yellow fleck virus Acronym: MYFV |
M. Hollings
Glasshouse Crops Research Institute, Littlehampton, Sussex, BN16 3PU, England
J. Horváth
University of Agricultural Sciences, Institute for Plant Protection, H-8361 Keszthely, P.O. Box 71, Hungary
Introduction Main Diseases Geographical Distribution Host Range and Symptomatology Strains Transmission by Vectors Transmission through Seed Transmission by Grafting Transmission by Dodder Serology Nucleic Acid Hybridization Relationships Stability in Sap | Purification Properties of Particles Particle Structure Particle Composition Properties of Infective Nucleic Acid Molecular Structure Genome Properties Satellites Relations with Cells and Tissues Ecology and Control Notes References Acknowledgements Figures |
Described by Hollings & Horváth (1978), and Hollings, Horváth & Besada (1978).
A virus with RNA-containing isometric particles c. 25 nm diameter, found in Melandrium album in Hungary. The virus is readily sap-transmissible to a wide range of herbaceous plant species. No vector is known.
No species gives diagnostic reactions, but a combination of the following species is useful:
Chenopodium quinoa. Numerous small, necrotic brown local lesions in 3-5 days (Fig.2), enlarging and coalescing to give necrotic areas. No systemic infection.
Cucumis sativus cv. Butchers Disease Resister. Sharply-defined yellowish local lesions in 4-7 days; occasional systemic infection, with chlorotic spots and flecks.
Melandrium album. Local necrotic rings after 5-7 days; systemic vein clearing and yellow flecks.
Nicotiana clevelandii. Chlorotic and necrotic local lesions in 3-5 days, becoming extensive necrotic areas. Systemic severe mottle, blistering, puckering, rosetting and much necrosis (Fig.1).
Phaseolus vulgaris (French bean) cv. The Prince. Numerous small brown necrotic local lesions in 3 days (Fig.3); no systemic infection.
Reactions in other commonly used test plants include:
Chenopodium amaranticolor, C. capitatum, C. murale. Necrotic local lesions (Fig.4). Systemic infection occasionally occurs in C. murale, with leaf dwarfing and chlorosis.
Datura stramonium. Local chlorotic spots and rings in about 1 week; no systemic infection.
Gomphrena globosa. Small, whitish necrotic local lesions in about 1 week; systemic coarse yellowish mottle and stunting.
Lycopersicon esculentum (tomato) cv. Moneymaker. Few chlorotic local lesions in about 1 week; no systemic infection.
Nicotiana glutinosa. Few chlorotic local lesions; no systemic infection.
N. glutinosa x N. clevelandii hybrid. Chlorotic local lesions after about 1 week; systemic bright yellow-green mottle in 2 weeks, with some dwarfing. Subsequent growth with only slight mottle.
N. tabacum (tobacco) White Burley. Chlorotic local lesions in 7-10 days, enlarging to chlorotic rings and ring-spots. No systemic infection.
Petunia hybrida cv. Fire Chief. A few chlorotic local lesions in 5-6 days; no systemic infection.
Pisum sativum (pea) cv. Onward. Systemic severe mottle, leaf distortion and stunting, with spreading necrosis killing the plant.
Tetragonia expansa. White necrotic local lesions after about 6 days; systemic vein yellowing, leaf twisting and malformation.
Tropaeolum majus. Irregular chlorotic local lesions and areas; systemic yellow vein-netting and leaf dwarfing.
N. clevelandii is useful for virus propagation and for maintaining cultures.
Chenopodium quinoa and Phaseolus vulgaris give satisfactory local lesions.
In immunodiffusion, a single line of precipitation is formed (Fig.5), and good reactions were obtained in 0.8% agar or agarose gels in distilled water or in 0.02 M phosphate buffer (Hollings & Horváth, 1978).
Further purification can be achieved by molecular permeation chromatography: apply 1.0-1.5 ml of the partially purified preparations to columns (85 x 1.5 cm) of controlled-pore glass beads (70 nm pore size), and elute the virus with 0.05 M Na-phosphate buffer, pH 7.6. The virus is eluted immediately after the void volume (Barton, 1977; M. Hollings & R. J. Barton, unpublished results). Yields of 200 mg virus/kg leaf can be obtained.
A260/A280: 1.66 to 1.69; Amax(260)/Amin(242): 1.39 to 1.43 (values corrected for light-scattering).
Electrophoretic behaviour: in immunoelectrophoresis in 0.8% Ionagar no. 2 in 0.02 M phosphate buffer pH 7.6 at 2°C, a single antigenic component was present, moving rather rapidly towards the anode (Fig.5) at approx. 9.5 x 10-5 cm2 v-1 sec-1.
Protein: Polyacrylamide gel electrophoresis showed a single polypeptide of M. Wt 22,000 ± 600 (Barton & Hollings, 1981), contrasted with 20,300 + 800 for brome mosaic virus.
Nicotiana clevelandii plants: (left) 7 days after infection, showing irregular necrotic local lesions, and developing systemic leaf mottle and puckering; (right) 20 days after infection, showing very severe stunting, rosetting, puckering, mottle and leaf necrosis.
Chenopodium quinoa: necrotic local lesions 5 days after infection.
Phaseolus vulgaris cv. The Prince: necrotic dot local lesions 11 days after infection.
Chenopodium murale: necrotic local lesions 8 days after infection.
Immunoelectrophoretogram: after 1 h electrophoresis in 0.8% (w/v) Ionagar no. 2 in 0.02 M phosphate buffer (pH 7.6) at 2°C, 4.4 v/cm. The single antigenic component migrates rather rapidly towards the anode.
Partially purified preparation of the virus stained in phosphotungstate (pH 6.5), showing isometric particles and tubular structures. Bar represents 200 nm.