Brome mosaic virus
J. B. Bancroft
Purdue University, Lafayette, Indiana, USA
McKinney, Fellows & Johnston (1942).
- Weidelgrasmosaik-Virus (Rev. appl. Mycol. 39: 589)
- Ryegrass streak virus (Rev. appl. Mycol. 44: 152)
- Trespenmosaik-Virus (Rev. appl. Mycol. 44: 2517)
- Marmor gramminis (Rev. appl. Mycol. 23: 427)
An RNA-containing virus with isometric particles about 25 nm in diameter. It is
by inoculation with sap and infects many monocotyledonous plants and a few
dicotyledonous ones. It is
found in temperate regions and is reported to be transmitted by nematodes
Causes a usually mild mosaic in most species of the Gramineae.
Reported from the USA and Europe.
Host Range and Symptomatology
Monocotyledonous host range is large, comprising about 60 genera in the Gramineae;
host range is restricted to a few genera in about 5 families
- Zea mays (maize). Seedlings of most varieties of sweet corn develop primary
lesions or streaks
followed by systemic necrosis and death
- Hordeum vulgare (barley). Mild mosaic.
- Chenopodium hybridum
and Datura stramonium
(Chiu & Sill, 1963)
are local lesion hosts.
Although the virus has been isolated from many locations and the existence of
no direct systematic comparisons have been published. In the USA, the McKinney isolate
(McKinney et al., 1942
is regarded as the type strain as opposed to the Sill isolate
(Chiu & Sill, 1963
which is usually assumed to be different.
Transmission by Vectors
The only positive transmission trials have been those reported by
Schmidt, Fritzsche & Lehmann (1963)
who claim Xiphinema paraelongatum (X. diversicaudatum
) and another species,
subsequently identified as X. coxi,
Transmission through Seed
Transmission by Dodder
The virus is moderately immunogenic
It produces single bands in gel-diffusion
tests at pH 5 but may produce 2 or 3 bands at neutrality or higher
All isolates of the virus cross react serologically. Quantitative differences have not been
reported, but may occur.
Stability in Sap
The thermal inactivation point (10 min) in barley sap is about 79°C, and the dilution
end-point is between 1 x 10-5
and 3 x 10-5
. The virus survives in
leaf tissue for more than 1 year.
The virus, which occurs in concentrations of about 1 g/l of barley juice, is extremely
purify. A convenient schedule, based on that of
Bockstahler & Kaesberg (1962)
is to blend tissue,
collected about 2 weeks after inoculation, in 0.2 M pH 4.8 acetate buffer, express the
through cheesecloth, allow it to stand for a few hours to overnight at 4°C, and
purify and concentrate by 2 to 3 cycles of differential ultracentrifugation.
Resuspend pellets in
0.1 M pH 5.0 acetate buffer and store at 4°C.
Properties of Particles
Sedimentation coefficient (s20, w
): (87.3-0.47c) S at pH 3-6 and
(78.7-0.64c) S at pH 7 and above
(Incardona & Kaesberg, 1964
where c = nucleoprotein
concentration in mg/ml. The virus sediments as a single component at pH 3-6 but may undergo
degradation and sediment as two or more components at pH 7 or above depending on
dialysis time and
exact ionic conditions. The virus is inactivated at pH 7.
Molecular weight (daltons): 4.6 x 106
(Bockstahler & Kaesberg, 1962).
Isoelectric point: about pH 7.9 at ionic strength of 0.1 (type strain).
Electrophoretic mobility: +1.41 x 10-5 cm2 sec-1
at pH 6 at an ionic strength of 0.1 (type strain).
Absorbance at 260 nm (1 mg/ml, 1 cm light path): 5.2 with no scattering correction.
Buoyant density: There are two density populations in CsCl at close to the average
value of 1.363
g/ml. The less dense population probably results from a terminal RNA deletion of about 250
nucleotides and is probably not infective.
Particles are isometric
about 250 nm in diameter in 1% pH 4.7 uranyl acetate, and are
built of 180 structure units in hexamer-pentamer clusters
(Bancroft, Hills & Markham, 1967
particles have a small, sometimes noticeable, electron-dense central area about 5 to 7.5
nm in diameter.
Molecular weight is 1 x 106
; presumably derivative RNA molecules of
0.3 x 106
and 0.7 x 106
occur together in some particles.
Molar percentages of nucleotides: G28; A27; C21; U24. RNA is 21-22% of particle weight.
coefficients (s20, w
) in 0.1 M KCl + 2 x 10-3
pH 5.5 are 26.8, 22.3 and 14 S for the 3 major classes of RNA
(Bockstahler & Kaesberg, 1965
Protein: Subunits have a molecular weight of about 20,300 and contain 189 amino
(Stubbs & Kaesberg, 1964).
Relations with Cells and Tissues
The virus is physically similar to
cowpea chlorotic mottle
broad bean mottle
serologically related to neither. Neither of these viruses infects barley or sweet corn.
- Bancroft, Hills & Markham, Virology 31: 354, 1967.
- Bockstahler & Kaesberg, Biophys. J. 2: 1, 1962.
- Bockstahler & Kaesberg, J. molec. Biol. 13: 127, 1965.
- Chiu & Sill, Phytopathology 53: 69, 1963.
- Hamilton, Virology 15: 452, 1961.
- Incardona & Kaesberg, Biophys. J. 4: 11, 1964.
- McKinney, Phytopathology 34: 993, 1944.
- McKinney, Fellows & Johnston, Phytopathology 32: 331, 1942.
- Moorhead, Phytopathology 46: 498, 1956.
- Ohmann-Kreutzberg, Phytopath. Z. 47: 1, 1963.
- Rochow, Phytopathology 49: 126, 1959.
- Schmidt, Fritzsche & Lehmann, Naturwissenschaften 50: 386, 1963.
- Stubbs & Kaesberg, J. molec. Biol. 8: 314, 1964.
Sweet corn leaves, (left) healthy, (right) infected, 5 days after
Sweet corn plants, (left) healthy, (right) infected, 10 days
Local lesions in Chenopodium hybridum.
Virus particles from a purified preparation in 1% pH 4.7 uranyl acetate.
Bar represents 100 nm.
Enlarged particle in inset shows detailed structure.