Desmodium yellow mottle virus
H. A. Scott
Department of Plant Pathology, University of Arkansas, Fayetteville, Arkansas 72701, USA
Walters & Scott (1972).
An RNA-containing virus with isometric particles c. 30 nm in diameter which sediment
as two components in the ultracentrifuge. It is restricted to legumes and is readily
sap-transmissible. No vector known. Found in USA.
Causes yellow mottling and some leaf deformity in Desmodium
spp. (tick trefoil).
The virus has not been obtained from plants of economic importance.
Host Range and Symptomatology
Only hosts known are members of the Leguminosae. Transmitted readily by sap inoculation.
- Phaseolus vulgaris (bean) cv. Great Northern and Vigna sinensis (cowpea) cv.
Monarch. Very mild systemic chlorotic mottling.
- P. vulgaris cv. Black Valentine, Bountiful and Pinto. Occasional local lesions on
- Phaseolus vulgaris cv. Great Northern.
- Desmodium tortuosum gives satisfactory local lesions
Transmission by Vectors
No vector reported. The bean leaf beetle, Cerotoma trifurcata,
cucumber beetle, Diabrotica undecimpunctata,
a weevil, Apion roseae,
green peach aphid, Myzus persicae,
did not transmit the virus
(Walters & Scott, 1972
Transmission through Seed
Transmission by Dodder
The virus is strongly immunogenic. A single band is formed in gel diffusion tests
Good reactions are obtained with crude sap.
The virus belongs to the
and is serologically distantly related to
turnip yellow mosaic
(Scott & Moore, 1972
andean potato latent
ononis yellow mosaic
wild cucumber mosaic
(Koenig & Givord, 1974
The virus is closely related to
kennedya yellow mottle
cocoa yellow mosaic
clitoria yellow vein
Stability in Sap
In Great Northern bean sap, the virus is infective after 10 min at 70°C, but not at
75°C, after dilution to 10-7
but not to 10-8
and after 38 days
but not 44 days at 20°C.
The virus is easily purified by one of the following methods:
1. A modification of Steeres butanol-chloroform method
(Walters & Scott, 1972).
2. Extract tissue with 0.2 M NaH2PO4 (1 gm/2 ml) and squeeze through
cheesecloth. Adjust extract to pH 5.0 with 0.1 N HCl and centrifuge at low speed. Subject
supernatant fluid to 3 cycles of alternate high and low speed centrifugation, resuspending
high speed pellets in 0.01 M phosphate buffer, pH 7.2
(Scott & Moore, 1972).
3. The bentonite method as described by
Dunn & Hitchborn (1965)
(Koenig & Givord, 1974).
Properties of Particles
Sedimentation behaviour typical of members of the
top (empty protein shells) 54 S and bottom (nucleoprotein) 114
S. Calculation not made at infinite dilution.
In immunoelectrophoresis, using Tris-sodium barbital buffer, pH 8.6, the virus migrated
towards the anode as a single component
Particles are isometric c.
30 nm in diameter
with icosahedral symmetry.
Top component particles are penetrated by 2% phosphotungstate, pH 6.8.
Particle CompositionNucleic acid:
RNA, single-stranded, 35% of the particle weight (calculated according
One centrifugal component, 23.3 S, in 0.01 M phosphate-0.1 M KCl,
pH 7.0; 17.7 S when heated in 1% formaldehyde. M. Wt c.
2 x 106
percentages of nucleotides: G16.5, A22.5, C37.2, U23.8
(Scott & Moore, 1972
Protein: No report.
Relations with Cells and Tissues
Crystals of virus-like particles occur in the nucleus, cytoplasm and often in the vacuoles
of cells of infected Phaseolus vulgaris
(D. Lesemann, personal
communication). Peripheral vesicles bounded by a double membrane occur in the chloroplasts,
as shown for other
Of the four adequately described viruses isolated from naturally-infected Desmodium
spp., desmodium yellow mottle virus may be distinguished by particle morphology from
desmodium mosaic virus
which was identified in Florida, USA, as a flexuous filamentous virus belonging
(Edwardson et al., 1970
It is readily distinguished from
bean pod mottle
(Moore, Scott & Walters, 1969
and cowpea chlorotic mottle
(Walters & Dodd, 1969
viruses found in Arkansas, USA, by serology.
- Dunn & Hitchborn, Virology 25: 171, 1965.
- Edwardson, Purcifull, Zettler, Christie & Christie, Pl. Dis. Reptr 54: 161, 1970.
- Koenig, Virology 72: 1, 1976.
- Koenig & Givord, Virology 58: 119, 1974.
- Moore, Scott & Walters, Pl. Dis. Reptr 53: 154, 1969.
- Reichmann, Virology 25: 166, 1965.
- Scott & Moore, Virology 50: 613, 1972.
- Walters & Dodd, Phytopathology 59: 1055, 1969.
- Walters & Scott, Phytopathology 62: 125, 1972.
Local lesions on Desmodium tortuosum.
Schlieren patterns obtained by analytical ultracentrifugation comparing purified
turnip yellow mosaic (upper) and desmodium yellow mottle (lower) viruses.
Virus particles stained with phosphotungstate. Bar represents 100 nm.
Reciprocal gel diffusion tests comparing turnip yellow mosaic virus (antiserum in
centre well at left) and desmodium yellow mottle virus (antiserum in centre well at right).
Homologous antigens in top and alternate wells.
Immunoelectrophoretic comparison of turnip yellow mosaic virus (top and bottom
bands) with desmodium yellow mottle virus (centre). Anode to the left.
Electron micrograph of virus-like particles in nucleus and cytoplasm of
Phaseolus vulgaris. Bar represents 1 µm. Photograph courtesy of D. Lesemann.