Soybean mosaic virus
Institute of Phytopathological Research, Wageningen, The Netherlands
- Described by Gardner & Kendrick (1921).
- Selected synonyms
- Soybean virus 1 (Rev. appl. Mycol. 15: 418)
- Soja virus 1 (Rev. appl. Mycol. 17: 52)
- A virus with flexuous particles c. 750 nm long, transmitted readily by
inoculation of sap, by many aphid species in the non-persistent manner, and
through seed of soybean (Glycine max), its only known natural host. The
virus is probably common wherever this crop is grown.
Causes mosaic of soybean.
In most countries where soybeans have been tested for viruses.
Host Range and Symptomatology
Long thought to be restricted to soybean, even when transmitted experimentally,
but now known to be transmissible to about 30 plant species, in about 10 of these
causing only local reactions or none at all (Quantz, 1961
; Galvez, 1963
). Chenopodium quinoa
and C. album
are the only
non-legume hosts. Readily transmissible by inoculation of sap or by aphid vectors
to the following:
- Diagnostic species
- Glycine max (soybean). Most varieties develop transient systemic
vein-clearing followed by a rolling or distorting mosaic in the younger leaves
with dark green, later puffed areas along the main veins and chlorosis between
the dark-coloured areas (Fig.1); plants are usually slightly stunted, pods are
fewer, sometimes malformed, glabrous and seedless. Some varieties develop
progressive necrosis (Gardner & Kendrick, 1921). Primary leaves of plants
grown from infected seed may show mottling and downward curling (Fig.2). In
Japan only 27 cultivars out of 110 tested (Koshimizu & Iizuka, 1963) were
resistant or immune. Symptoms are more severe at 18-20°C than at
27-30°C (Conover, 1948; Walters, 1963).
- Phaseolus vulgaris (French bean). Latent local infection in some
cultivars, followed by latent systemic infection in a few of these. Systemic
symptoms, somewhat reminiscent of bean common mosaic virus,
are produced only
in Double White Princess (Quantz, 1961; Galvez, 1963; Debrot & De Rojas,
- Phaseolus lathyroides. Systemic chlorotic mottling or mosaic and
leaf curling (Quantz, 1961; Galvez, 1963).
- Chenopodium album. Local lesions, but virus could not be recovered
from them (Galvez, 1963).
- Chenopodium quinoa. Weak and diffuse chlorotic local lesions
- Propagation species
- Glycine max (soybean). Various cultivars have been used. Lincoln plants
were harvested 15 days after inoculation (Galvez, 1963). In Bansei, virus
infectivity was highest in inoculated leaves 25 days after inoculation and
decreased sharply after 31 days; in systemically infected leaves infectivity
was correlated with the intensity of mosaic symptoms and remained high from 3
to at least 6 weeks after inoculation (Quiniones & Dunleavy, 1970).
- Assay species
- Glycine max (soybean). Most cultivars react with characteristic systemic
- Phaseolus vulgaris (French bean). Necrotic local lesions develop on
inoculated attached primary leaves of Kentucky Wonder waxpole bean (Ross, 1967).
Eight varieties including Processor and Topcrop, produce necrotic local lesions
when detached leaves are incubated on moist filter paper in closed Petri dishes
under artificial light at 30-32°C (Fig.3; Quantz, 1961).
- Other local-lesion hosts sometimes used are Cyamopsis tetragonoloba,
Dolichos biflorus and D. lablab (Dunleavy, Quiniones & Krass,
1970; Quiniones & Dunleavy, 1970; Ross, 1967).
Some minor strains have been distinguished on the basis of differences in
pathogenicity and virulence towards soybean selections, Lespedeza stipulacea
and Japanese soybean cultivars (Quiniones & Dunleavy, 1970
; Ross, 1968
Transmission by Vectors
Some 16 aphid species, including Acyrthosiphon pisum, Aphis fabae
, have been reported to transmit the virus in the
non-persistent manner (Heinze & Köhler, 1940
; Conover, 1948
& Iizuka, 1963
; De Vasconcelos, 1964
Transmission through Seed
Common and probably the most important source of initial crop infection. Up
to 30% or sometimes more of the seeds of diseased plants are infected, depending
on cultivar and duration of infection before flowering (Gardner & Kendrick,
; Kendrick & Gardner, 1924
; Koshimizu & Iizuka, 1963
). Plants infected
after flowering do not produce infected seeds. The virus is present in seed-coat
and embryo, and green seeds contain more virus than mature ones (Koshimizu &
). Seed-coat mottling is stimulated by virus infection, hut there is
no direct correlation between this mottling and the presence of virus in
particular seeds (Koshimizu & Iizuka, 1963
; Kennedy & Cooper, 1967
). Distribution of infected seeds in pods and on plants is erratic
(De Vasconcelos, 1964
Transmission by Dodder
So far little information is available. Antisera prepared by Ross (1967)
Quiniones & Dunleavy (1970)
using purified virus had a titre of 1/2048 when
tested against purified antigen. The titre of Rosss antiserum was 1/4096 when
tested with virus-containing clarified sap. Microprecipitin tests were used
because intact virus particles do not diffuse in agar gel.
Working with two strains, Quiniones & Dunleavy (1970)
antiserum titres of 1/2048 and titres of 1/256 after cross absorption with
heterologous antigens. Bercks (quoted by Quantz, 1961
) found serological
relationships between soybean mosaic, bean yellow mosaic
and bean common mosaic
viruses, but this preliminary finding has not been confirmed.
In particle morphology and size, mode of transmission and other biological and
biophysical properties, soybean mosaic virus resembles members of the
potato virus Y group (potyviruses),
especially those closely related to bean yellow
mosaic virus (Bos, 1970b). This is particularly true of the
seed-transmitted viruses of bean common mosaic (Bos, 1971), cowpea aphid-borne
mosaic (Lovisolo & Conti, 1966) and pea leafroll mosaic (Bos, 1970a),
and the incompletely described viruses of adzuki bean (Phaseolus
angularis) mosaic (Matsumoto, 1922), asparagus bean (Vigna
sesquipedalis) mosaic (Snyder, 1942; lnouye, 1969) and mung bean
(Phaseolus aureus) mosaic (Kaiser et al., 1968). They all seem to
have a rather limited natural host range, possibly because seed transmission
makes alternative hosts superfluous.
In cross-protection tests, Quantz (1961) found that soybean mosaic and bean
yellow mosaic viruses produced a striking but varying protection against bean
common mosaic virus. Similarly, the number of local lesions produced by soybean
mosaic and bean common mosaic viruses in detached Topcrop bean leaves in Petri
dishes was considerably decreased when the leaves were systemically infected
with bean yellow mosaic virus. Quantz (1961) also found that using detached
leaves of 23 bean cultivars, the same cultivars were hypersensitive to both
soybean mosaic virus and bean common mosaic virus. However, of ten other
varieties systemically susceptible to bean common mosaic virus, only one
contracted systemic infection by the soybean virus. Moreover, soybean was
found to be only locally susceptible to bean common mosaic virus.
Stability in Sap
The thermal inactivation point (10 min) is usually 55-60°C, but sometimes
a few degrees higher; the dilution end-point is usually around 10-3
but values of 10-5
have also been published; sap
commonly loses infectivity after 2-3 days at room temperature but sometimes
retains it as long as 4 days. In expressed sap the virus was most stable at pH
6.0 (Galvez, 1963
Like other viruses of the potato virus Y group
, soybean mosaic virus easily
aggregates and sediments during initial low-speed centrifugation. Thus much
virus is lost when organic solvents are used to denature colloidal plant
constituents (Galvez, 1963
; Quiniones & Dunleavy, 1970
). For good results,
according to Ross (1967)
, grind each 100 g cooled leaves in 200 ml cold 0.5 M
sodium citrate buffer containing 1% mercaptoethanol, and strain the extract
through cheesecloth. Slowly add n
-butanol (7 ml/100 ml extract) while
slowly stirring. Refrigerate overnight. Clarify and sediment by two cycles of
differential centrifugation, resuspending the sediments obtained at high speed
in borate buffer (0.01 M, pH 8.3). Then further purify by centrifugation in
sucrose density gradients.
Properties of Particles
Particles are flexuous filaments (Fig.5
. 746 nm long (Quantz,
; De Vasconcelos 1964
), sometimes shorter in purified preparations.
Nucleic acid content (based on A260
) is 6-7%
Relations with Cells and TissuesKoshimizu & Iizuka (1963)
Quiniones & Dunleavy (1970)
single amorphous globular inclusion in each epidermis cell of young soybean
). In ultrathin sections of soybean, Dunleavy et al.
found circular membrane-bound and pinwheel micro-inclusions.
Soybean mosaic virus differs from bean yellow mosaic
and bean common mosaic
viruses in that (i) it fails to cause systemic symptoms in Phaseolus vulgaris
cultivars (excepting Double White Princess), (ii) bean common mosaic virus
does not infect soybean systemically, and (iii) bean yellow mosaic virus
infects Vicia faba.
- Bos, Neth. J. Pl. Path. 76: 8, 1970a.
- Bos, CMI/AAB Descriptions of Plant Viruses 40, 4 pp., 1970b.
- Bos, CMI/AAB Descriptions of Plant Viruses 73, 4 pp., 1971.
- Conover, Phytopathology 38: 724, 1948.
- Debrot & De Rojas, Agronomia trop. 17: 75, 1967.
- De Vasconcelos, Anais. Inst. sup. Agron. Univ. téc. Lisb. 26: 181, 1964.
- Dunleavy, Quiniones & Krass, Phytopathology 60: 883, 1970.
- Galvez, Phytopathology 53: 388, 1963.
- Gardner & Kendrick, J. agric. Res. 22: 111, 1921.
- Heinze & Köhler, Phytopath. Z. 13: 207, 1940.
- Inouye, Rev. Pl. Prot. Res., Tokyo 2: 42, 1969.
- Kaiser, Danesh, Okhovat & Mossahebi, Pl. Dis. Reptr 52: 687, 1968.
- Kendrick & Gardner, J. agric. Res. 27: 91, 1924.
- Kennedy & Cooper, Phytopathology 57: 35, 1967.
- Koshimizu & Iizuka, Bull. Tohoku natn. agric. exp. Stn 27: 1, 1963.
- Lovisolo & Conti, Neth. J. Pl. Path. 72: 265, 1966.
- Matsumoto, Phytopathology 12: 295, 1922.
- Quantz, Phytopath. Z. 43: 79, 1961.
- Quiniones & Dunleavy, Pl. Dis. Reptr 54: 301, 1970.
- Ross, Phytopathology 57: 465, 1967.
- Ross, Pl. Dis. Reptr 52: 344, 1968.
- Ross, Phytopathology 59: 829, 1969.
- Ross, Phytopathology 60: 1798, 1970.
- Snyder, Phytopathology 32: 518, 1942.
- Walters, Pl. Dis. Reptr 47: 726, 1963.
Soybean, cv. Norin No. 4, with severe systemic symptoms. (Photo
courtesy Dr N. Iizuka.)
(Right) soybean seedling, cv. Kimusume, grown from infected
seed; (left) healthy seedling (after Koshimizu & Iizuka, 1963).
Phaseolus vulgaris, cv. Furore, detached leaf with necrotic
local lesions produced at 32°C. (Photo courtesy Dr L. Quantz.)
Intracytoplasmic inclusion bodies (I) in soybean leaf epidermis;
N=nucleus (after Koshimizu & Iizuka, 1963).
Electron micrograph of purified virus preparation after negative
staining; bar represents 500 nm. (Photo courtesy Dr J. P. Ross.)