Red clover vein mosaic virus
Division of Mycology and Plant Pathology, Indian Agricultural Research Institute, New Delhi-12, India
- Described by Osborn (1937).
- Selected synonyms:
- Marmor trifolii (Rev. appl. Mycol. 28: 514)
- ? Pea streak virus 1 (Rev. appl. Mycol. 17: 220)
- Trifolium virus 2 (Rev. appl. Mycol. 19: 230)
- Wisconsin pea stunt virus (Rev. appl. Mycol. 30: 419 and
- An RNA-containing virus with tubular particles about 645 nm long and 12 nm
wide. Most of its hosts are legumes. Easily transmissible by sap inoculation
and by aphids in the non-persistent manner.
Causes vein mosaic, mosaic, streaking and stunting in various legumes
and Fig. 4
Widely distributed in Europe, North America and South Africa.
Host Range and Symptomatology
Host range is restricted to Amaranthaceae, Chenopodiaceae, Leguminosae
- Diagnostic species
Various species have been used (Gibbs, Varma & Woods, 1966;
Sänder, 1959; Stuteville & Hanson, 1965; Varma & Gibbs, 1967).
- Chenopodium amaranticolor and C. quinoa. Some isolates give
chlorotic lesions; not systemic.
- Gomphrena globosa. Purple spreading
local lesions (Fig.3); systemic in plants kept in dark for 2 days before
inoculation (Wilcoxson & El-Kandelgy, 1966).
- Pisum sativum (pea). Plants are stunted, and show vein chlorosis and
curling of young leaves (Fig.1 and Fig.4). No symptoms appear in winter.
- Trifolium dubium, T. hybridum and Melilotus alba. Systemic vein
clearing and mild mottle.
- T. pratense (red clover). Vein mosaic and mottle in young leaves of
plants in open; mild symptoms in glasshouse (Fig.2).
- Vicia faba (broad bean). Chlorotic mottle in tip leaves. Symptomless
- V. sativa (common vetch). Brown necrotic local lesions; sometimes
- Propagation species
- Trifolium pratense and T. repens are useful hosts for maintaining
cultures; Pisum sativum is a good source of virus for purification.
- Assay species
- Chenopodium amaranticolor (for some isolates) and Gomphrena globosa
can be used as local lesion hosts.
Only minor variants have been distinguished. Zaumeyer, Goth & Ford (1964)
identified a strain P42 differing from the common strain in producing streak in
and Vicia faba
and being latent in
Trifolium pratense. Gibbs et al. (1966
) distinguished isolates
infecting and not infecting Chenopodium amaranticolor.
Transmission by Vectors
Transmitted by the following aphid species: Acyrthosiphon pisum,
Therioaphis ononidis, Myzus persicae
(Graves & Hagedorn, 1956
Bos & van der Want, 1959
), Cavariella aegopodii
and C. theobaldi.
It is transmitted in the non-persistent manner, is acquired by the vectors
in less than 2 min and inoculated in less than 5 min. Starving the aphids before
the acquisition feed aids transmission. Transmission by vectors is not very
Transmission through Seed
Not common. Seed-borne in Trifolium pratense
The virus is a good immunogen. Tube precipitation tests, in which the virus
gives flocculent precipitates, are the most reliable. Chloroplast agglutination
can also be used. Virus preparations treated with ultrasonic vibrations give
specific bands of precipitate in gel diffusion tests using 0.7% agar-gel buffered
with neutral 0.06 M diaminoethane-tetraacetate/borate buffer (Varma, Gibbs &
Isolates of the virus from England, Germany, the Netherlands and the USA
are serologically similar (Varma et al., 1970
; Wetter, Quantz &
). The virus is distantly serologically related to cactus 2, carnation
, chrysanthemum B
, passiflora latent, potato M
, and potato S
closely serologically related to pea streak virus
. It is also reported to be
serologically related to muskmelon vein necrosis virus (Freitag & Milne,
Stability in Sap
The virus, in extracts of infected pea, is inactivated when heated for 10 min
at between 60°C and 65°C, stored 24 hr at 20°C or diluted beyond
Several methods are satisfactory. One (Varma et al., 1970
) is to
triturate fresh or frozen inoculated and systemically infected leaves of peas
(harvested 15-25 days after inoculation of the plants) with twice their weight
of neutral phosphate-ascorbate buffer. Emulsify with a quarter volume of
chloroform. Centrifuge at low speed and collect the aqueous phase. Sediment
the virus from this at 76,000 g
for 90 min. Resuspend in neutral
0.005 M borate buffer. Purify either by rate zonal centrifugation in sucrose
gradients or by restricted diffusion chromatography in agar gel. Purified virus
is best stored in 0.005 M borate buffer.
Properties of Particles
Sedimentation coefficient (s20,w
) at infinite dilution:
160 S; no accessory component (Varma et al., 1970
Isoelectric point: about pH 4.5.
Ultraviolet radiation inactivates the virus; some of the damage is
photoreactivable (Varma et al., 1970).
Particles are straight or slightly curved tubular filaments about 12 nm
wide with a modal length of 645 nm (Fig.5
). Phosphotungstate penetrates the
particles revealing an axial canal about 3.5 nm wide. Particles stained with
uranyl formate show helically arranged subunits; grooves between the subunits
and almost parallel to the long axis of the particle are more distinct than
those of the basic helix. About 10 subunits per turn of the basic helix of
pitch 3.4 nm (Varma et al., 1968
Single-stranded, about 6.25% of particle weight. Molar percentage
of nucleotides G 31; A 24; C 23; U 22 (Varma et al., 1970
Protein: About 93.75% of particle weight. About 2000 subunits per
Relations with Cells and Tissues
Crystalline and amorphous inclusions are found in pea and in leaf hairs of
red clover. X-bodies, bundles of particles and rings of coiled particles are
observed in ultrathin sections (Rubio-Huertos, 1964
; Sänder, 1959
The virus resembles (Wisconsin) pea streak virus
but can be distinguished
by particle length, serology and reactions in Gomphrena globosa
(Wisconsin) pea streak virus has particles c.
nm long (Wetter et al., 1962
) and produces local lesions in the above
hosts more quickly than does red clover vein mosaic virus (Stuteville &
- Freitag & Milne, Phytopathology 60: 166, 1970.
- Gibbs, Varma & Woods, Ann. appl. Biol. 58: 231, 1966.
- Graves & Hagedorn, Phytopathology 46: 257, 1956.
- Hagedorn, Bos & van der Want, Tijdschr. PlZiekt. 65: 13, 1959.
- Matsulevich, Agrobiology, Moscow 2: 75, 1957.
- Osborn, Phytopathology 27: 1051, 1937.
- Rubio-Huertos, Microbiologia esp. 17: 1, 1964.
- Sänder Phytopathology 49: 748, 1959.
- Stuteville & Hanson, Phytopathology 55: 336, 1965.
- Varma, Gibbs, Woods & Finch, J. gen. Virol. 2: 107, 1968.
- Varma, Gibbs & Woods, J. gen. Virol. 8: 21, 1970.
- Varma, P. & Gibbs, Ann. appl. Biol. 59: 23, 1967.
- Wetter, Quantz & Brandes, Phytopath. Z. 44: 151, 1962.
- Wilcoxson & El-Kandelgy, Phytopathology 56: 364, 1966.
- Zaumeyer, Goth & Ford, Pl. Dis. Reptr 48: 494, 1964.
Systemic infection in tip leaves of Pisum sativum. cv. Lincoln.
Mild vein mosaic in systematically infected leaf of Trifolium
Local lesions in inoculated leaf of Gomphrena globosa.
Necrosis and rosetting of systematically infected P. sativum
cv. Big Ben.
Virus particles stained with phosphotungstate. Bar represents 200 nm.