Tomato ringspot virus
Canada Agriculture Research Station, Vancouver, B.C., Canada
- Described by
- Selected synonyms
- Tobacco ringspot virus No. 2 (Rev. appl. Mycol. 15: 831)
- Nicotiana virus 13 (Rev. appl. Mycol. 36: 303)
- Annulus zonatus (Rev. appl. Mycol. 28: 514)
- Peach yellow bud mosaic virus (Rev. appl. Mycol. 24: 65)
- Grape yellow vein virus (Rev. appl. Mycol. 35: 286)
- An RNA-containing virus with isometric particles about 28 nm in diameter. It
is readily transmissible by inoculation of sap and has a wide host range,
including both woody and herbaceous plants. It is transmitted by the nematode
Causes mosaic or ringspot symptoms in tobacco, Pelargonium, Hydrangea,
raspberry and blackberry; rasp leaf in cherry; yellow bud mosaic in peach;
yellow vein in grapevine; stunt or stub head in Gladiolus;
Field spread restricted to the temperate regions of North America where the
nematode vector Xiphinema americanum
is prevalent. Endemic in native
wild hosts along the California coast
(Frazier, Yarwood & Gold, 1961
probably been distributed in ornamental crops to other parts of the world
although to date there have been no confirmed reports.
Host Range and Symptomatology
Experimental host range is wide; spp. in more than 35 dicotyledonous and
monocotyledonous families are susceptible. In nature, the virus occurs mostly in
ornamentals and woody or semiwoody plants. Transmissible by sap inoculation,
readily to herbaceous hosts but with difficulty to woody hosts.
- Chenopodium amaranticolor
and C. quinoa. Small
chlorotic local lesions; systemic apical necrosis.
- Cucumis sativus (cucumber). Local chlorotic spots; systemic
chlorosis and mottle.
- Phaseolus vulgaris (bean). Chlorotic local lesions; systemic
rugosity and necrosis of tip leaves
- Nicotiana tabacum (tobacco). Necrotic local spots or rings
systemic etched ring and line patterns. Leaves produced later are symptomless
but contain virus.
- Petunia hybrida
Local necrotic lesions; necrotic collapse
of young leaves.
- Lycopersicon esculentum (tomato). Local necrotic flecks; systemic
mottle and necrosis
- Vigna sinensis (cowpea;
Fig.7). Chlorotic or necrotic local
lesions; most isolates cause systemic tip necrosis.
- Propagation species
- Nicotiana tabacum or woody plants such as raspberry or currant are
suitable for maintaining cultures; Cucumis sativus (cucumber) or Petunia
are good sources of virus for purification.
- Assay species
- Vigna sinensis, Nicotiana tabacum, Chenopodium amaranticolor, and
C. quinoa are useful local lesion hosts. Cucumber is useful as a source and
bait plant for nematode transmission experiments
(Téliz, Grogan & Lownsbery, 1966).
Variants giving slightly different symptoms in herbaceous hosts have been
found. The best known variants, distinguished not by host reactions but on the
basis of the field disease attributed to the virus, are as follows:
Tobacco strain = tobacco ringspot virus No. 2 of
Occurred spontaneously in tobacco seedlings in a greenhouse. Source Eastern
Peach yellow bud mosaic strain. Occurs naturally in almond, apricot
and peach. Herbaceous host reactions similar to those caused by Prices strain
from which it cannot be distinguished serologically
(Cadman & Lister, 1961).
Source Western USA.
Grape yellow vein strain. Occurs naturally in grape. Herbaceous host
reactions similar to above strains but differs in causing no top necrosis in
cowpea; also differs somewhat serologically. Source Western USA.
Transmission by Vectors
Transmitted by adults and three larval stages of the nematode Xiphinema
Nematodes can acquire virus within 1 h and can inoculate it into
healthy plants within 1 h. Single nematodes can transmit
(Téliz et al., 1966
and tomato ringspot viruses can both be
transmitted by the same single nematode
Transmission through Seed
Transmitted occasionally through tobacco and raspberry seed, frequently
(Mellor & Stace-Smith, 1963
seed. Pollen transmission not investigated.
Transmission by Dodder
A virus thought to be tomato ringspot virus was not transmitted by Cuscuta
californica, C. subinclusa,
or C. campestris
The virus is moderately immunogenic; antiserum titres in excess of 1:1000
may be attained. Diagnostic serological reactions can be obtained in ring
precipitin, micro precipitin, tube precipitin, gel-diffusion or complement
fixation tests. Antisera prepared by intravenous or intramuscular injections
give a single band of precipitate in gel-diffusion tests.
Tomato ringspot virus is not related serologically to the nematode-borne
viruses that occur in Europe
(Cadman & Lister, 1961
nor to tobacco ringspot
(Tall, Price & Wertman, 1949
or tomato top necrosis
two similar viruses that occur in North America. Prior to the widespread
use of serology, plant protection tests were used to distinguish tomato ringspot
and tobacco ringspot viruses; reciprocal tests in recovered tobacco plants
or petunia plants
(Cadman & Lister, 1961
show lack of
Unilateral protection occurs between tomato ringspot and
elm mosaic viruses
but serological comparisons, reveal no cross reactions and vector relationships
suggest that the two viruses are distinct
(Fulton & Fulton, 1970).
The tobacco and peach yellow bud mosaic strains do not differ antigenically
but the grape yellow vein strain, although closely related to the others, may be
distinguished by the formation of spurs in gel-diffusion tests
Téliz et al., 1966).
Stability in Sap
In tobacco sap, the virus loses infectivity after 10 min at about 58%, 2
days at 20°C, 3 weeks at 4°C, or several months at -20°C.
Dilution end-point of sap from inoculated tobacco leaves or cucumber cotyledons
; that of sap from systemically infected tobacco is less than
The virus is relatively unstable and is destroyed by many routine
purification procedures. Two methods seem satisfactory:
1. Gooding (1963).
Freeze leaves and stems from infected bean plants and
homogenize each 100 g in 50 ml distilled water containing 0.75 g sodium
ascorbate. Squeeze through cheesecloth, add n-butanol to 8.5% (v/v) and
centrifuge at low speed. Concentrate by four cycles of high- and low-speed
centrifugation, resuspending the pellets obtained at high speed in 0.02 M
phosphate buffer, pH 7.2. Subject the final product to sucrose density gradient
2. Stace-Smith (1966).
Extract each 100 g infected cucumber tissue in 150 ml
0.5 M borate buffer, pH 6.7. Squeeze extract through cheesecloth, freeze
overnight, thaw, and centrifuge at low speed. Add granular ammonium sulphate, 15
g/100 ml extract, stir overnight and centrifuge at low speed. Concentrate the
supernatant fluid by two cycles of high- and low-speed centrifugation,
resuspending the pellets obtained at high speed in 0.01 M versene buffer, pH
7.0. Subject the final product to sucrose density gradient centrifugation. Yield
is 10-20 mg/kg of infected leaves.
Properties of Particles
Purified preparations contain two major classes of particles, empty protein
shells without RNA (T) and the infective nucleoprotein (B). The two classes of
particle are serologically indistinguishable; only the B particles are infective
Sedimentation coefficients (s20,w) at infinite dilution (svedbergs):
53 (T), 126-128 (B).
Molecular weights (daltons): About 3.2 x 106 (T), 5.5 x 106 (B).
Isoelectric point: c. pH 5.1.
Electrophoretic mobility: -2.60 x 10-5 cm2 volt-1 sec-1
in 0.1 ionic strength phosphate buffer, pH 7.38; or
1.59 x 10-5 cm2 volt-1 sec-1 at pH 6.55 (B and T).
A260/A280: about 1.05 (T), 1.8 (B).
Absorbance at 260 nm (1 mg/ml, 1 cm light path): about 10.0 (B).
Particles are isometric, about 28 nm in diameter
somewhat when mounted in phosphotungstate for electron microscopy. They are
penetrated by phosphotungstate and contrast poorly.
: Only the 126 S particle contains RNA. Molecular weight about
2.3 x 106
. Molar percentages of nucleotides: G 26; A 23; C 22; U 29.
RNA is about 40% of the particle weight
(Tremaine & Stace-Smith, 1968
Protein: About 60% of particle
weight. For amino acid composition, see
Tremaine & Stace-Smith (1968).
Relations with Cells and Tissues
Particles thought to be those of tomato ringspot virus were observed in low
concentration in the cytoplasm and plasmodesmata of infected leaf tissue of Datura
(de Zoeten & Gaard, 1969
Tomato ringspot virus is similar in size, shape, physical properties, host
reaction and patchy distribution in the field to other
serologically unrelated to any of them. Serological tests are therefore
essential for positive identification of isolates thought to belong to this
group of viruses. The geographical distribution, natural host range, and vector
relationships of tomato ringspot virus closely parallel those of
tobacco ringspot virus
If antisera are not available to distinguish isolates of these
viruses, differential host reactions may be useful
The name tomato ringspot has been applied to two apparently unrelated
viruses, one isolated from tobacco seedlings by
and the other from
tomato plants by
Samson & Imle (1942).
Prices isolate, or isolates
serologically related to it, has been used for physical, chemical, and
biological characterization of tomato ringspot virus. The isolate of Samson &
Imle was probably related not to Prices tomato ringspot virus but to
tomato top necrosis virus
- Bancroft, Phytopathology 58: 1360, 1968.
- Bennett, Phytopathology 44: 905, 1944.
- Cadman & Lister, Phytopathology 51: 29, 1961.
- de Zoeten & Gaard, J. Cell Biol. 40: 814, 1969.
- Frazier, Yarwood & Gold, Pl. Dis. Reptr 45: 649, 1961.
- Fulton, Phytopathology 57: 535, 1967.
- Fulton & Fulton, Phytopathology 60: 114, 1970.
- Gooding, Phytopathology 53: 475, 1963.
- Kahn, Phytopathology 46: 295, 1956.
- Karle, Phytopathology 50: 466, 1960.
- McLean, Pl. Dis. Reptr 46: 877, 1962.
- Mellor & Stace-Smith, Can. J. Bot 41: 865, 1963.
- Price, Phytopathology 26: 665, 1936.
- Samson & Imle, Phytopathology 32: 1037, 1942.
- Stace-Smith, Can. J. Bot. 40: 905, 1962.
- Stace-Smith, Virology 29: 240, 1966.
- Tall, Price & Wertman, Phytopathology 39: 288, 1949.
- Téliz, Grogan & Lownsbery, Phytopathology 56: 658, 1966.
- Tremaine & Stace-Smith, Virology 35: 102, 1968.
Local and systemic symptoms in Chenopodium amaranticolor.
Local and systemic symptoms in Phaseolus vulgaris.
Virus particles from a purified preparation in uranyl acetate. Bar
represents 100 nm.
Local lesions in Nicotiana tabacum (Havana 425).
Necrotic local lesions and systemic necrosis in Petunia
Systemic mottle in Lycopersicon esculentum.
Chlorotic local lesions in inoculated primary leaves of Vigna