Details of DPV and References
DPV NO: 105 October 1972
Species: Wild cucumber mosaic virus | Acronym: WCMV
Wild cucumber mosaic virus
M. H. V. van Regenmortel Laboratoire des Virus des Plantes, 8, rue Goethe, 67-Strasbourg, France
- 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
An RNA-containing virus with isometric particles about 28 nm in diameter which sediment as two components in the ultracentrifuge. It is found only in the USA, has a host range largely restricted to the Cucurbitaceae and is transmitted mechanically and by flea beetles. It is distantly serologically related to turnip yellow mosaic and cacao yellow mosaic viruses.
Host Range and Symptomatology
Largely restricted to the Cucurbitaceae
(Lindberg et al., 1956);
however, an Oregon isolate
also symptomlessly infects Vinca rosea.
Isolates from California (Milne et al., 1969) can be distinguished from those of Oregon (Allen & Fernald, 1971) by host range and symptoms. Two serologically distinguishable strains have been reported from California (Grogan, Taylor & Kimble, 1964).
Transmission by Vectors
Transmission through Seed
Transmission by Dodder
The virus is strongly immunogenic. After prolonged immunization, antisera prepared against the virus also react with the depolymerized protein subunits of the virus in gel-diffusion tests (Bekker, 1967).
Distantly serologically related to turnip yellow mosaic virus (MacLeod & Markham, 1963; van Regenmortel, 1966) and cacao yellow mosaic virus (Brunt et al., 1965). The nucleic acid resembles that of turnip yellow mosaic virus in its large cytidylic acid content (Symons et al., 1963).
Stability in Sap
In Cucurbita pepo sap, the virus is inactivated when heated at 70°C for 10 min; sap of infected plants retains its infectivity at room temperature for 28 days. The dilution end-point is 10-4 (Lindberg et al., 1956).
Sap from infected pumpkin plants may be clarified by adding ethanol to 20% (v/v) (Symons et al., 1963), by acidification to pH 4.9 (Grogan et al., 1964), or by adding bentonite (Dunn & Hitchborn, 1965). The virus can be precipitated with ammonium sulphate and concentrated by differential centrifugation. Pellets should be resuspended in a buffer because the virus precipitates in the absence of salt.
Properties of Particles
Two major classes of particles occur in purified preparations, empty protein shells (top component, T) and infective nucleoprotein (bottom component, B) (Sinclair, Geil & Kaesberg, 1957; Anderegg et al., 1961). Intermediate components have also been reported (Yamazaki & Kaesberg, 1961b; Markham, 1962, 1967; MacLeod & Markham, 1963). The top component is more readily adsorbed by bentonite than is the bottom component; a marked differential in adsorption is observed in 10-3 M MgSO4, 10-2 M phosphate, pH 7.3. Under these conditions the electrophoretic mobility of the two components is also different (Hitchborn & Dunn, 1965).
Sedimentation coefficients (s20, w) at infinite dilution (svedbergs): 119 (B), 53 (T) (Yamazaki & Kaesberg, 1961a).
Diffusion coefficient (D20, w): 1.27 x 10-7 cm2 sec-1 (T and B).
Isoelectric point: pH 6.6 in 0.1 M Na phosphate buffer (T and B).
Electrophoretic R Ø value in zone electrophoresis: 0.14 (van Regenmortel, 1968).
Partial specific volume (calculated): 0.740 (T) and 0.670 (B) (Yamazaki & Kaesberg, 196la).
The particles are isometric, c. 28 nm in diameter (Fig. 3). The empty shells are penetrated by negative stains used in electron microscopy whereas the full particles are not. In crude preparations outer shells of 41 nm diameter have been found, associated preferentially with empty particles (Hitchborn & Hills, 1965).
RNA: 35% of particle by weight. Molar percentage of nucleotides: G16.4, A17.0, C41.0, U25.6 (Symons et al., 1963).
Protein: 65% of particle by weight. 190 amino acid residues per subunit of Mol. Wt 20,200 (Symons et al., 1963).
Relations with Cells and Tissues
There are numerous similarities between this virus and turnip yellow mosaic virus, although they have totally different host ranges. Points of similarity include: size and shape, RNA composition, size of protein subunit, common antigenic determinants, beetle vector and induction of chloroplast abnormalities.
Photographs courtesy of J. S. Hahn and M. B. von Wechmar.
References list for DPV: Wild cucumber mosaic virus (105)
- Allen, Virology 47: 467, 1972.
- Allen & Fernald, Pl. Dis. Reptr 55: 546, 1971.
- Anderegg, Geil, Beeman & Kaesberg, Biophys. J. 1: 657, 1961.
- Bekker, M. Sc. Thesis, University of Stellenbosch, 75 pp., 1967.
- Brunt, Kenten, Gibbs & Nixon, J. gen. Microbiol. 33: 81, 1965.
- Dunn & Hitchborn, Virology 25: 171, 1965.
- Freitag, Phytopathology 31: 8, 1941.
- Freitag, Phytopathology 42: 8, 1952.
- Grogan, Taylor & Kimble, Phytopathology 54: 163, 1964.
- Hitchborn & Dunn, Virology 26: 441, 1965.
- Hitchborn & Hills, Virology 26: 756, 1965.
- Lindberg, Hall & Walker, Phytopathology 46: 489, 1956.
- MacLeod & Markham, Virology 19: 190, 1963.
- Markham, Adv. Virus Res. 9: 241, 1962.
- Markham, In Methods in Virology 2: 1, ed. K. Maramorosch & H. Koprowski, Academic Press, New York and London, 1967.
- Milne, Grogan & Kimble, Phytopathology 59: 819, 1969.
- Sinclair, Geil & Kaesberg, Phytopathology 47: 372, 1957.
- Symons, Rees, Short & Markham, J. molec. Biol. 6: 1, 1963.
- Ushiyama & Matthews, Virology 42: 293, 1970.
- Van Regenmortel, Proc. internat. Conf Plant Viruses, Wageningen, 1965: 213, 1966.
- Van Regenmortel, S. Afr. med. J. 42: 118, 1968.
- Walters, Adv. Virus Res. 15: 339, 1969.
- Yamazaki & Kaesberg, Biochim. biophys. Acta 51: 9, 1961a.
- Yamazaki & Kaesberg, Biochim. biophys. Acta 53: 173, 1961b.