Broad bean stain virus
A. J. Gibbs
John Curtin School of Medical Research, Australian National University, Canberra, Australia
Helen G. Smith
Little Paddock, Kirklington, Newark, Nottinghamshire, England
Lloyd, Smith & Jones (1965) and
Gibbs, Giussani-Belli & Smith (1968).
- Broad bean Evesham stain virus (Rev. appl. Mycol. 44: 3213)
A virus with angular isometric RNA-containing particles, about 25 nm in diameter,
which sediment as three components when centrifuged. It is readily transmitted by
inoculation of sap and is seed-borne, but no specific vector has been found. It
seems to infect only legumes, and occurs in Europe and North Africa.
Infects broad bean plants (Vicia faba
) causing chlorotic mottling and
mosaic of the leaves
), and necrotic staining of the seed testa
Europe and North-West Africa.
Host Range and Symptomatology
Hosts restricted to Leguminosae;
Gibbs et al. (1968)
species in 19 dicotyledonous families, but the virus infected only 7 species of
legume: Crotalaria spectabilis, Lupinus hirsutus, Melilotus alba, Phaseolus
(French bean), Pisum sativum
(pea), Trifolium incarnatum
(crimson clover) and Vicia faba
- Phaseolus vulgaris. Varieties Tendergreen and Canadian Wonder show
chlorotic local lesions, and a systemic chlorotic mosaic. The Prince is infected
only locally, and Pinto, Idaho Refugee, Blue Lake and Tendercrop not at all.
- Pisum sativum. All varieties tested are susceptible, and develop a
systemic chlorotic mottle, with stem and leaf necrosis in cool weather.
- Chenopodium amaranticolor, Gomphrena globosa, Nicotiana tabacum
(tobacco) and N. clevelandii are not susceptible.
- Pisum sativum Onward, Phaseolus vulgaris cv. Tendergreen and
- Phaseolus vulgaris cv. Tendergreen, in which the virus gives local
lesions, and Vicia faba, which is infected systemically.
Transmission by Vectors
Vector not known, though the virus spreads over large distances within
(Gibbs et al., 1968
Transmission through Seed
Common in certain varieties of broad bean, transmitted to up to 10% of
the progeny of infected plants.
Transmission by Dodder
Moderately immunogenic. Gives a single band of precipitate in Ouchterlony
gel diffusion tests, and a granular precipitate in tube tests.
The physical and chemical properties of the particles of this virus resemble
cowpea mosaic virus
It is distantly serologically related to
red clover mottle virus
and cowpea mosaic virus
Gibbs et al., 1968
Valenta & Gressnerova, 1966
Stability in Sap
In broad bean sap the thermal inactivation point (10 min) is between 60°
and 65°C. Infectivity survives at least 31 days at 4°C and more than one
year at -15°C. The dilution end-point in sap from leaves showing obvious
symptoms is somewhat variable but usually around 10-3
The virus particles are stable and Steeres butanol/chloroform method may be
used to extract them from plant tissue into a pH 7.0 buffer containing a reducing
agent. They may then be sedimented and purified by differential centrifugation
(Gibbs et al., 1968
Properties of Particles
The particles are all the same size but sediment as three components
Sedimentation coefficients (s20,w
) are about 60, 100 and
Particles are isometric, about 25 nm in diameter with
angular polygonal outlines
The 60 S particles are penetrated by
negative stain, and then show a central cavity with a surrounding shell 2.0-2.5
nm thick. The 100 S particles are partially penetrated by stain, and the
127 S particles not at all. The particles show no regularly arranged
Probably single-stranded. Molar percentages of nucleotides: G23.3;
A26.5; C18.4; U31.9. Their sedimentation coefficients suggest that the 127 S
particles contain about 35% RNA, and the 100 S particles about 25%; the
60 S particles contain none.
Protein. The size and composition of the protein subunits are not yet
Relations with Cells and Tissues
Readily confused with
because both viruses cause similar leaf symptoms in broad bean, are seed-borne,
and have similar particles. However, Echtes Ackerbohnemosaic-Virus rarely infects
is serologically unrelated to broad bean stain virus,
and preparations of its particles contain few or no (60 S) RNA-free particles
- Devergne, Annls Épiphyt. 16: 41, 1965.
- Devergne, Annls Épiphyt. 17: 147, 1966.
- Gibbs, Giussani-Belli & Smith, Ann. appl. Biol. 61: 99, 1968.
- Lloyd, Smith & Jones, Hort. Res. 5: 13, 1965.
- Valenta & Gressnerova, Acta virol., Prague 10: 182, 1966.
Photographs: courtesy of Rothamsted Experimental Station, UK.
Broad bean (Vicia faba) plant infected with broad bean stain
virus through the seed.
Two systemically infected broad bean leaves.
Seeds of infected broad beans showing the characteristic brown
necrosis of the testa around the periphery of the seed.
Sedimentation behaviour of the virus (upper schlieren diagram)
compared with that of Echtes Ackerbohnemosaik-Virus (lower diagram);
sedimentation is from left to right (note that the menisci of the two
diagrams are displaced).
Electron micrograph of a phosphotungstate-stained purified
preparation of the virus. Bar represents 100 nm.