Potato yellow dwarf virus
L. M. Black
Dept. of Botany, University of Illinois, Urbana, Illinois 61801, USA
Disease described by Barrus & Chupp (1922).
There are two closely related but distinct forms of potato yellow dwarf virus,
one transmitted by Aceratagallia sanguinolenta but not by Agallia constricta
(sanguinolenta yellow dwarf virus; SYDV) and one with the inverse vector
relationships (constricta yellow dwarf virus; CYDV)
This description is for SYDV except where stated otherwise.
Aureogenus vastans (Rev. appl. Mycol. 23: 490)
SYDV has been called A. vastans var. vulgare (Rev. appl. Mycol.
23: 490) and New York potato yellow dwarf virus (Rev. appl. Mycol. 21: 36).
CYDV has been called A. vastans var. agalliae
(Rev. appl. Mycol. 28: 514) and New Jersey potato yellow dwarf virus
(Rev. appl. Mycol. 21: 36). Consult CMI Phytopath. Paper 9, 204 pp.,
1968, for other synonyms
A virus with bacilliform particles (380 x 75 nm) containing lipid, protein and RNA.
Transmitted in the persistent manner by agallian leafhoppers (in which it multiplies)
and by manual inoculation to Nicotiana rustica. Host range wide; found
sporadically in potato in North America.
Yellow dwarf of potato.
Virus spreads from plant to plant in northeastern USA and adjacent parts of
Canada. Elsewhere it develops in potato plants grown from infected tubers. CYDV has
been found only in New Jersey, but probably has a wider distribution.
Host Range and Symptomatology
All known plant hosts are dicotyledons. Nicotiana rustica
and N. glutinosa
can be infected by leaf abrasion inoculations, N. rustica
much the more susceptible, but, in addition to solanaceous plants, vectors have
transmitted the virus to species in the families Compositae, Cruciferae, Labiatae,
Leguminosae, Polygonaceae and Scrophulariaceae
Varieties of Solanum tuberosum show economically important differences in
disease incidence in the field
Medicago sativa cv. Grimm is immune
(Black, 1943a). The ox-eye daisy,
Chrysanthemum leucanthemum var. pinnatifidum is the principal source of virus for infecting
potato crops (Younkin, 1943).
Clover, the preferred host of the vector (Watkins, 1941),
is rarely infected (Younkin, 1943).
High temperatures favour the development of the disease in potato and low temperatures retard it
(Walker & Larson, 1939). Severe
winters may greatly reduce the overwintering population of clover leafhoppers. Drought
forces migration of vectors into potato fields. The virus survives the winter in
infected ox-eye daisies, potato tubers and adult leafhoppers.
Solanum tuberosum (potato). Apical yellowing and necrosis, internal necrotic spots
in stems, particularly in upper nodes. Dwarfing or killing of sprouts before emergence.
Internal necrotic spots in tubers; malformation, cracking, dwarfing of tubers. Plant
rarely survives; when it does, chronic symptoms are milder.
Nicotiana rustica. SYDV causes yellow primary lesions (Fig.2) first detectable
in about 1 week in suitable leaves inoculated by rubbing. Systemic symptoms are mottling
and yellowing of leaves (Fig.1), sometimes with light green or yellow streaking of stems.
Chronic symptoms are milder. CYDV causes primary lesions of variable appearance and is
more slow to infect plants systemically (Fig.1).
Trifolium incarnatum. May be inoculated by vectors or by pricking inoculum into
the crown of the plant. With SYDV, vein-clearing appears first in younger leaves (Fig.6)
and plant usually dies. With CYDV, systemic symptoms appear first in older leaves and
rusty-brown spots and lines (Fig.6) develop which never result from SYDV infection;
plant usually survives acute infection by CYDV and chronic infection is very mild.
Nicotiana rustica leaves of suitable age.
Monolayers of vector cells. Cells from A. sanguinolenta are designated AS
cells, those from A. constricta, AC cells. Infected cells are countable 2 days
after inoculation if stained by specific fluorescent antiserum
(Chiu et al., 1970).
Nevertheless, no serological reactions in tissues of viruliferous vectors have been demonstrated.
The infectivity of SYDV for AC cells is about l0% that for AS cells, that of CYDV for AS
cells about 10% of that for AC cells (Liu & Black, 1969).
Strains of differing virulence may be isolated from primary lesions of SYDV
Strains that are transmitted poorly or not at all by the vector arise when the
virus is maintained in N. rustica
for long periods without passage through the
vector (Black, 1953b
Transmission by Vectors
Crimson clover is the best host for testing vectors. SYDV is transmitted well by
), and several other
spp., poorly by Agallia quadripunctata
and not at all by
CYDV is transmitted by Agallia constricta
but not by
Aceratagallia sanguinolenta. Agallia quadripunctata
transmits CYDV somewhat better
than SYDV. The viruses multiply in the vectors
(Chiu et al., 1970
). Nymph, adult
male and adult female insects transmit. The virus can overwinter in adult vectors even
in the absence of food plants
). Minimum incubation period in the vector is
6 days. In some tests SYDV (Black, 1943b
and CYDV (Nagaraj & Black, 1962
were not transmitted through egg or sperm of the vector but in others CYDV was
occasionally transmitted through the egg
). Individuals of
and A. constricta
differ genetically in ability to transmit
SYDV and CYDV respectively
Nagaraj & Black, 1962
recovered infective CYDV from various organs of A. constricta
Transmission through Seed
No seed transmission found in N. rustica.
Transmission by Dodder
Rabbit antisera with titres of 1/1280 can be produced by intramuscular injection of
purified virus in adjuvant. Antisera react with virus and soluble antigen from plants but
neither reaction has been demonstrated with extracts from vectors
(Wolcyrz & Black, 1956
Tests with virions or soluble antigen show that SYDV and CYDV are serologically
related but not identical
(Wolcyrz & Black, 1957
). CYDV and strains of SYDV protect
from severe infection with a necrotizing strain of SYDV whereas several
unrelated viruses do not (Black, 1940
Stability in Sap
In sap of N. rustica,
infectivity is retained at 23-27°C for 2½-12
hr, dilution end-point is usually about 10-3
, thermal inactivation point
(10 min) about 50°C. Virus does not withstand desiccation in N. rustica
or prolonged storage in frozen leaves.
Purified by density-gradient zonal centrifugation and electrophoresis
). Certain solutions, e.g.
0.1 M glycine and 0.01 M
, noticeably stabilize infectivity
). Later methods are in
essence modifications of Brakkes techniques.
Properties of Particles
The particles seem to be of one type. The dilution curve indicates that one particle
initiates infection (Chiu et al., 1970
Sedimentation coefficient (s20,w
): 810-950 S.
Buoyant density (in sucrose): 1.17 (Brakke, 1958).
Molecular weight (calculated from dimensions and density): c. 1100 x
Purified virus does not give a peak in its light absorption spectrum at any
wavelength between 220 and 320 nm.
Bacilliform particles (Fig.4
380 x 75 nm in plant sections,
but smaller in sections of vector cell monolayers. Viral envelope appears to consist of
three lamellae c.
3.5 nm thick and c
. 5 nm apart
(MacLeod, Black & Moyer, 1966
Electron micrographs of the particles of this virus taken at different
times (Black, Mosley & Wyckoff, 1948
Brakke, Black & Wyckoff, 1951
Brakke & Vatter (in Black, 1955
Black et al., 1965
Macleod et al., 1966
) illustrate various properties of the particles.
The virus contains more than 20% lipid
(Ahmed et al., 1964
). It contains at
least three different proteins and single-stranded RNA with a M.Wt of c
. 4.3 x
daltons (R. MacLeod, personal communication).
Relations with Cells and Tissues
Fluorescein-conjugated antibody studies show that antigen is at first confined to
the nucleus of cells in culture. Both in the plant host and in the vector the principal
site of virus assembly appears to be at the inner nuclear membrane and the principal
site of virus accumulation is between the two nuclear membranes (Fig.5
However, intranuclear assembly also occurs, and in later stages virus is found in the cytoplasm
(MacLeod et al., 1966
Chiu et al., 1970
SYDV and CYDV are the only leafhopper-borne viruses that are manually transmissible
and produce primary lesions in inoculated leaves
). Their particles are
morphologically similar to those of some other leafhopper and aphid-borne viruses
(such as maize mosaic
Russian winter wheat mosaic,
lettuce necrotic yellows
sowthistle yellow vein
viruses) and also to those of some viruses of animals (such as
bovine vesicular stomatitis virus) but there is no other evidence to show how they may
- Ahmed, Black, Perkins, Walker & Kummerow, Biochem. biophys. Res. Commun. 17: 103, 1964.
- Barrus & Chupp, Phytopathology 12: 123, 1922.
- Black, Am. Potato J. 11: 148, 1934.
- Black, Mem. Cornell Univ. agric. Exp. Stn. 209: 1, 1937.
- Black, Phytopathology 28: 863, 1938.
- Black, Am. J. Bot. 27: 386, 1940.
- Black, Am. Potato J. 18: 231, 1941.
- Black, Phytopathology 33: 363, 1943a.
- Black, Genetics, Princeton 28: 200, 1943b.
- Black, Proc. Am. phil. Soc. 88: 132, 1944.
- Black, Phytopathology 43: 9, 1953a.
- Black, Phytopathology 43: 466, 1953b.
- Black, Phytopathology 45: 208, 1955.
- Black, A. Rev. Phytopath. 7: 73, 1969.
- Black, Mosley & Wyckoff, Biochim. biophys. Acta 2: 121, 1948.
- Black, Smith, Hills & Markham, Virology 27: 446, 1965.
- Brakke, J. Am. chem. Soc. 73: 1847, 1951.
- Brakke, Archs Biochem. Biophys. 45: 275, 1953.
- Brakke, Archs Biochem. Biophys. 55: 175, 1955.
- Brakke, Virology 2: 463, 1956.
- Brakke, Virology 6: 96, 1958.
- Brakke, Black & Wyckoff, Am. J. Bot. 38: 332, 1951.
- Chiu, Liu, MacLeod & Black, Virology 40: 387, 1970.
- Hansing, Phytopathology 32: 7, 1942.
- Hansing, Bull. Cornell Univ. agric. Exp. Stn 792, 28 pp., 1943.
- Larson, J. agric. Res. 71: 441, 1945.
- Liu & Black, Phytopathology 59: 1038, 1969.
- MacLeod, Virology 34: 771, 1968.
- MacLeod, Black & Moyer, Virology 29: 540, 1966.
- Nagaraj & Black, Virology 16: 152, 1962.
- Sinha, Virology 27: 118, 1965.
- Taylor, Am. Potato J. 15: 37, 1938.
- Walker & Larson, J. agric. Res. 59: 259, 1939.
- Watkins, Bull. Cornell Univ. agric. Exp. Stn 758, 24 pp., 1941.
- Wolcyrz & Black, Phytopathology 46: 32, 1956.
- Wolcyrz & Black, Phytopathology 47: 38, 1957.
- Younkin, Am. Potato J. 19: 6, 1942.
- Younkin, Fm Res. 9: 6, 1943.
Nicotiana rustica leaves, (left to right) healthy, systemically
infected with SYDV and with CYDV.
Primary lesions of SYDV in N. rustica.
Section of N. rustica leaf showing cross and longitudinal sections of
SYDV particles. Bar represents 200 nm. (Courtesy R. MacLeod.)
Section of N. rustica leaf showing accumulation of SYDV particles
between separated inner and outer nuclear membranes. Bar represents 400 nm.
Trifolium incarnatum, (left) healthy, (centre) infected
with SYDV, (right) infected with CYDV.