Cucumber mosaic virus
A. J. Gibbs
Rothamsted Experimental Station, Harpenden, Hertfordshire, England
B. D. Harrison
Scottish Horticultural Research Institute, Invergowrie, Dundee, Scotland
Doolittle (1916) and
- Selected synonyms
- Cucumber virus 1 (Rev. appl. Mycol. 6: 501)
- Cucumis virus 1 (Rev. appl. Mycol. 17: 52)
- Marmor cucumeris (Rev. appl. Mycol. 28: 514)
- Spinach blight virus (J. agric. Res. 14: 1)
- Tomato fern leaf virus (Rev. appl. Mycol. 9: 417)
An RNA-containing virus with isometric particles about 30 nm in diameter.
It has a wide host range, is transmitted by many species of aphid in the non-persistent manner and is readily
transmissible by inoculation of sap. It is widespread and common in temperate regions.
Causes mosaic of cucumber and other cucurbits, blight of spinach, fern leaf of tomato,
celery, woodiness of passion fruit (in part), mosaics of many dicotyledonous and
ornamental species; also occurs in many other crop species.
World-wide, especially in temperate regions.
Host Range and Symptomatology
Host range is wide; species in more than 40 dicotyledonous and monocotyledonous families
susceptible to infection
Readily transmissible by inoculation of sap, for example
to the following:
- Cucumis sativus (cucumber). Green or yellow/green systemic mosaic
- Nicotiana tabacum (tobacco;
N. glutinosa and N. clevelandii.
Inoculated leaves are symptomless, or develop chlorotic or necrotic lesions;
green or yellow/green
systemic mosaic or ringspots, usually without necrosis.
- Lycopersicon esculentum (tomato). Systemic mosaic and much narrowed leaf
- Phaseolus vulgaris (French bean). In U.K., pin-point necrotic local lesions
winter but not in summer; not systemic
- Chenopodium amaranticolor and C. quinoa. Chlorotic or necrotic local
systemic. Vigna sinensis (cowpea). Local lesions in some cultivars; most isolates
- Nicotiana glutinosa or N. tabacum cv. Xanthi-nc are suitable plants for
cultures; N. tabacum, N. clevelandii and Cucurbita pepo are good sources of
- Vigna sinensis, Phaseolus vulgaris, Chenopodium amaranticolor and C. quinoa
local-lesion hosts. Some strains cause necrotic local lesions in Nicotiana tabacum.
Many minor variants can be distinguished. The best known major variants are:
Yellow strain of
= strain 6 of Price. Produces brilliant yellow mosaics in
Nicotiana spp. and necrotic lesions in inoculated leaves of Zinnia elegans.
Y strain> of
Symptoms produced in Nicotiana spp. resemble those of the
yellow strain but are usually less intense. Systemic in V. sinensis. Source USA.
Spinach strain of
Necrotic local lesions in N. tabacum; systemic
green mosaic or ringspots with distortion and some necrosis of the veins.
Severe systemic symptoms in
several species. Source UK.
Transmission by Vectors
Transmissible by more than 60 spp. of aphids, notably Aphis gossypii
(Kennedy, Day & Eastop, 1962
All instars can transmit. Virus can be acquired in less than 1
min and inoculated in less than 1 min. No latent period. Feeding vectors retain
virus for less than 4 h.
Not transmitted to progeny aphids. Some isolates can lose their transmissibility by one
but retain their transmissibility by another
Transmission through Seed
Probably not common. Reported for instance in White Acre pea,
Transmission by Dodder
At least 10 species of Cuscuta
The virus infects the dodder
The virus is poorly immunogenic. It is precipitated by 0.15 M (0.85%) NaCl
(Francki et al., 1966
which should not be used as a diluent in tube precipitin tests; 0.05 M phosphate buffer
(pH 8), although not ideal, can be used. Agarose (1%), prepared in water, is satisfactory
tests. In tests with virus protein, 1.5 M KCl should be used as the diluent in tube
and for preparing agarose. Specific precipitates of virus in serological tests in liquids
(somatic). In gel-diffusion tests two bands of precipitate may develop when
antisera prepared by
intramuscular injection are used: a curved band near the antigen well (intact virus)
and a straighter
one nearer to the antiserum well (degraded virus). Antisera prepared by intravenous
injection may react
only with the slower diffusing antigen
Using narrow-spectrum antisera, the strains of
cucumber mosaic virus
fall into two broad groups.
The first group contains Prices yellow and Y strains, and the second contains
most of the virus strains
isolated from crop and garden plants in the U.K. When broad-spectrum antisera are used,
relationships can be shown between some viruses of the two groups. Some strains of the
second group are
distantly serologically related to strains of
tomato aspermy virus
from chrysanthemum and tomato
(Brunt, Hollings and Stone, personal communication;
In plant-protection tests, strains protect against the effects of one another
either completely or
partially. Prices yellow strain (necrotic lesions in Zinnia elegans) and
the spinach strain
(necrotic lesions in tobacco) are often used as the challenge viruses. Some workers have
of protection between cucumber mosaic virus and tomato aspermy virus but several others
Stability in Sap
In tobacco sap, the thermal inactivation point (10 min) is about 70°C,
dilution end-point about
, and infectivity is retained at 20°C for 3-6 days. Infectivity is
by adding reducing agents (for example 0.1% thioglycollic acid) or chelating agents
(for example 0.01 M
sodium diethyl dithiocarbamate) to the leaf extraction medium.
Two methods seem satisfactory. Inoculated tobacco leaves may yield 100-400 mg virus per kg
1. Scott (1963).
Grind tissue in 0.5 M citrate buffer (pH 6.5; containing 0.1% thioglycollic acid)
together with an equal volume of chloroform. Dialyse aqueous phase against 0.005 M borate
buffer (pH 9).
Sediment and clarify by three cycles of high- and low-speed centrifugation, resuspending
obtained at high speed in the borate buffer. Work at 0-4°C.
2. Murant (1965).
Extract tissue in 0.5 M phosphate buffer (pH 7.5) containing 0.1% thioglycollic acid.
Filter, and shake filtrate with an equal volume of ether. Centrifuge at low speed.
Sediment and clarify
by two cycles of high- and low-speed centrifugation, resuspending the pellets obtained at
high speed in
0.06 M phosphate buffer (pH 7.5). Centrifuge at low speed, adjust supernatant fluid to
pH 5 and
centrifuge again at low speed. Resuspend pellet in 0.06 M buffer and centrifuge at
low speed. Work at
Zone electrophoresis can be used to free partially purified virus from host materials
(Van Regenmortel, 1966).
Properties of Particles
Sedimentation coefficient (s20, w
) at infinite dilution: about 98 S.
Molecular weight: 5.8-6.7 x 106 daltons.
Diffusion coefficient (D20 x 10-7cm2/sec): 1.23.
Isoelectric point: about pH 4.7.
Partial specific volume (calculated): 0.701.
Electrophoretic mobility: -8 x 10-5 cm2/sec/volt at pH 7 in 0.1 M
buffer (S strain);
other strains probably differ.
Absorbance at 260 nm (1 mg/ml, 1 cm light path): 5.0.
Particles are isometric, about 30 nm in diameter
and are built of 180 subunits in
pentamer-hexamer clusters; particle centre is hollow
(Finch et al., 1967
The particles of most
strains disintegrate when mounted in phosphotungstate for electron microscopy,
unless previously fixed
(for instance, 2% formaldehyde for 30 min). The particles are penetrated by
phosphotungstate and contrast
Molecular weight about 1 x 106
, about 18% of particle weight,
stranded. Molar percentages of nucleotides: G23.4; A24.3; C23.2; U29.1.
Sedimentation coefficient of
RNA (s20, w
) is 23 S in 0.02 M KH2
NaOH buffer of
pH 7.2, but subsidiary components of 13 S and 20 S reported
(Kaper et al., 1965
Protein: Subunits have molecular weight about 3.2 x 104, and
contain about 287
amino acid residues. Amino acid composition (moles %): ala 6.0; arg 8.4; asx 10.4;
cys 0; glu 7.1; gly
5.6; his 1.4; ile 5.5; leu 9.2; lys 6.3; met 2.7; phe 2.5; pro 6.4; ser 11.1;
thr 6.1; trp 0; tyr 3.8;
(Van Regenmortel, 1967).
Other components: None reported.
Relations with Cells and Tissues
All tissues infected except, possibly, meristematic regions. No inclusion bodies
particles occur in cytoplasm.
NotesTomato aspermy virus
has a host range and properties similar to those of cucumber mosaic virus.
However, it causes more distortion of systemically infected leaves of
enations develop. Unlike cucumber mosaic virus it is confined to inoculated leaves of
and Datura stramonium.
It occurs commonly in chrysanthemum, in which cucumber mosaic virus is
Alfalfa mosaic virus
may be confused with cucumber mosaic virus, because it too is widespread, causes
similar symptoms in some hosts and is also transmitted by aphids in the non-persistent manner.
most strains of alfalfa mosaic virus, unlike cucumber mosaic virus, give local lesions in
vulgaris at all times of the year, and infect Chenopodium amaranticolor and
systemically. Also, alfalfa mosaic virus has distinctive bacilliform particles.
- Anderson, Phytopathology 47: 515, 1957.
- Badami, Ann. appl. Biol. 46: 554, 1958.
- Bhargava, Ann. appl. Biol. 38: 377, 1951.
- Doolittle, Phytopathology 6: 145, 1916.
- Finch, Klug & Van Regenmortel, J. mol. Biol. 24: 303, 1967.
- Francki, Randles, Chambers & Wilson, Virology 28: 729,1966.
- Hollings, Ann. appl. Biol. 43: 86, 1955.
- Jagger, Phytopathology 6: 148, 1916.
- Kaper, Diener & Scott, Virology 27: 54, 1965.
- Kennedy, Day & Eastop, A conspectus of aphids as vectors of plant viruses. London, Commonwealth Institute of Entomology, 1962.
- Lawson, Virology 32: 357, 1967.
- Murant, Virology 26: 538, 1965.
- Price, Phytopathology 24: 743, 1934.
- Price, Amer. J. Bot. 27: 530, 1940.
- Schmelzer, Phytopath. Z. 28: 1, 1956.
- Scott, Virology 20: 103, 1963.
- Scott, Virology, 34: 79, 1968.
- Van Regenmortel, Virology 23: 495, 1966.
- Van Regenmortel, Virology 31: 391, 1967.
Systemically infected leaves of Cucumis sativus.
Virus particles from a purified preparation, fixed with formaldehyde and
phosphotungstate. White bar represents 100 nm.
Local and systemic symptoms in Nicotiana tabacum (White Burley)
Bhargavas spinach strain.
Systemic symptoms in N. tabacum (White Burley) infected with
Prices yellow strain.
Inoculated leaf of Phaseolus vulgaris (The Prince), showing
pin-point necrotic lesions.
Systemically infected shoot of Lycopersicon esculentum, showing
fern leaf symptoms.