Cymbidium mosaic virus
R. I. B. Francki
Department of Plant Pathology, Waite Agricultural Research Institute, University of Adelaide, South Australia
- Cymbidium black streak virus (Rev. appl. Mycol. 30: 469)
- Orchid mosaic virus (Rev. appl. Mycol. 23: 261)
An RNA-containing virus with flexuous filamentous particles c. 475 x 13 nm. Readily
transmissible by sap inoculation to a narrow range of host plants. Causes diseases in several
genera of orchids. No known vector. World-wide distribution.
and necrosis in several genera of orchids
Jensen & Gold, 1955
Kado & Jensen, 1964
Together with a strain of
tobacco mosaic virus
causes blossom brown necrotic streak in
(Thornberry & Phillippe, 1964
World-wide in cultivated orchids.
Host Range and Symptomatology
Infects species in the Orchidaceae and a few in other families. Transmissible by sap
inoculation, for example, to the following:
- Chenopodium amaranticolor. Slow-developing, large, blotchy lesions in inoculated
leaves, not earlier than 20 days after inoculation
- Cassia occidentalis, C. tora and C. bicapsularis. Small lesions in
inoculated leaves within 5 days after inoculation
- Datura stramonium. Slow-developing, necrotic lesions in inoculated leaves, not
earlier than 10 days after inoculation
- Cymbidium plants are suitable for maintaining cultures and as a source of virus for
Datura stramonium has also been used as a
source of virus for purification (Francki, unpublished).
- Chenopodium amaranticolor, Datura stramonium and Cassia occidentalis are all
suitable local-lesion assay plants.
Transmission by Vectors
No known vector.
Transmission through Seed
Transmission by Dodder
The virus is strongly immunogenic. Serological tube-precipitin or gel-diffusion tests
are convenient. A single precipitin band is produced in gel-diffusion tests.
A member of the
potato virus X group:
a distant serological relationship to
potato virus X
has been reported and it has particles of similar length
(Brandes & Bercks, 1965
Stability in Sap
sap, the thermal inactivation point (10 min) is 65-70°C and sap
remains infective for at least 7 days at room temperature. Stable in the presence of organic
solvents such as chloroform.
Easily purified by differential centrifugation. Yields of up to 360 mg virus may be
obtained from 1 kg of Cymbidium
(Kado & Jensen, 1964
Properties of Particles
Appear similar to those of
potato virus X
but details are unknown.
Particles are flexuous filaments with helical symmetry about 475 nm long and 13 nm wide
as observed in electron micrographs
Contains about 6% RNA (Francki, unpublished).
Relations with Cells and Tissues
NotesTobacco mosaic virus
is also common in orchids but can easily be distinguished from
cymbidium mosaic virus by testing on herbaceous hosts, serological testing or examination
of leaf-dip preparations by electron microscopy.
- Brandes & Bercks, Adv. Virus Res. 11: 1, 1965.
- Corbett, Phytopathology 50: 346, 1960.
- Francki, Aust. J. biol. Sci. 19: 555, 1966.
- Jensen, Phytopathology 41: 401, 1951.
- Jensen & Gold, Phytopathology 45: 327, 1955.
- Kado & Jensen, Phytopathology 54: 974, 1964.
- Murakishi, Phytopathology 48: 132, 1958a.
- Murakishi, Phytopathology 48: 137, 1958b.
- Thornberry & Phillipe, Pl. Dis. Reptr 48: 936, 1964.
Infected Cymbidium plant.
Mild mosaic in Cymbidium leaf.
Lesions in inoculated leaf of Chenopodium amaranticolor.
Lesions in inoculated leaf of Cassia occidentalis.
Lesions in inoculated leaf of Datura stramonium.
Virus particles from purified preparation in uranyl acetate. Bar represents 500 nm.