Beet leaf curl virus
Institut für Phytopathologie Aschersleben der Akademie der Landwirtschaftswissenschaften, Germany
Disease first described by Wille (1928
). Virus characterized by
Eisbein & Proll (1978)
- Selected synonyms
- Beet Kräuselkrankheit virus (Rev. appl. Mycol. 7: 692)
- Beet leaf crinkle virus (Rev. appl. Mycol. 7: 692)
- Beta virus 3 (Rev. appl. Mycol. 36: 303)
- Rübenkräusel-Virus (Rev. Pl. Path. 56: 3275)
A virus with bacilliform particles c. 225 x 80 nm. Transmitted in the
persistent (propagative) manner by the bug Piesma quadratum (Heteroptera),
but not by inoculation of sap. Host range moderate, mainly in the Chenopodiaceae.
The virus affects sugar beet in Central Europe on sandy soils only, but is no longer
of economic importance.
Causes leaf curl disease and stunting in Beta vulgaris
(sugar beet, fodder beet, etc.)
and in Spinacia oleracea.
Restricted to Germany, Poland and
sporadic occurrences in Czechoslovakia and USSR. The apparent northern limit of
distribution is the 18°C isotherm for the month of July. Found especially in
crops on light sandy soils, because these are preferred by Piesma quadratum.
Host Range and Symptomatology
Confined to the Chenopodiaceae and Aizoaceae, the most important hosts being sugar
beet and fodder beet. Also infects other members of the genus Beta,
and Tetragonia tetragonioides
(syn. T. expansa
Schmutterer & Ehrhardt, 1966
Transmitted by Piesma quadratum
but not by inoculation with sap.
- Beta vulgaris (sugar beet). The first symptom is vein clearing in the youngest
leaves (Fig.1); soon afterwards the leaves begin to curve inwards, forming closed braids
that resemble a head of lettuce (Fig.2). Because new leaves are constantly being formed,
the bushy plant may continue to grow upwards. The growth of the root ceases prematurely.
- Chenopodium quinoa. Systemic vein clearing (Fig.3) and leaf curling; severe stunting.
- Beta vulgaris (sugar beet) is ideal for maintaining cultures.
- Sugar beet and fodder beet are the best plants for transmission tests with Piesma quadratum.
No strains reported.
Transmission by Vectors
Transmitted by the bug Piesma quadratum
) in the persistent
(propagative) manner. The virus multiplies in its vector, and the bugs remain
infective for life. There is no evidence of transmission to progeny insects. Minimum
acquisition feeding period, 30 min; minimum inoculation feeding period, 40 min. There
is a latent period of 7 to 35 days. Both the adult and nymphal stages can acquire and
transmit the virus (Proeseler, 1966a
Transmission through Seed
Not known to occur.
Transmission by Dodder
Five species of Cuscuta
did not transmit (Proeseler, 1966a
No antiserum has been prepared.
Sugar beet savoy virus (Coons et al., 1958
which is transmitted by Piesma cinereum
in North America, is poorly characterized and its relationship,
if any, to beet leaf curl virus is unknown. Particle morphology places beet leaf curl
virus in the plant rhabdovirus group
, possibly in
sub group II because
the particles accumulate in the perinuclear space.
Stability in Sap
Determined by injecting virus-free Piesma quadratum
with beet sap. The
thermal inactivation point (10 min) is between 54 and 58°C, the dilution end-point
of unconcentrated sap is between 10-4
in sap is retained for less than 24 h at 25°C or more than 28 days at - 20°C
PurificationEisbein & Proll (1978)
used the following procedure which is based on that used
by Lee (1968)
for purification of
wheat striate mosaic virus
. Extract 5-10 g fresh or
frozen beet leaves or roots with 20 ml 0.05 M phosphate buffer, pH 7.0, containing 0.15
M D-mannitol, 0.001 M ethylenediamine-tetraacetate, 0.01 M MgCl2
, and 0.1%
bovine serum albumin. Concentrate and clarify the virus by two cycles of high and low
speed centrifugation, resuspending the pellets obtained at high speed in the same buffer.
Subject the final product to density gradient centrifugation.
Properties of Particles
Two narrow zones are produced by sedimentation in sucrose density gradients
(Eisbein & Proll, 1978
The upper zone contains intact bacilliform particles (about 186 x 75
nm in negative stain) and numerous deformed virus particles and fragments; the lower zone
contains aggregated particles. Attempts to purify the virus further led to disruption of
the virus particles, and a decrease of infectivity
(Eisbein & Proll, 1978
In ultrathin sections the particles are bacilliform (Fig.5
), 80 nm in diameter, with
an average length of 225 nm in diseased leaves, and 350 nm in roots. They have an
electron-dense core with a central channel and an enveloping membrane with small
protrusions. Many bullet-shaped particles are also observed (Eisbein, 1976
Relations with Cells and Tissues
Large concentrations of particles occur in the phloem parenchyma of leaves as
well as in the parenchyma cells of roots. They accumulate predominantly in the
perinuclear spaces and also in the cisternae of the endoplasmic reticulum. In the
cytoplasm every group of virus particles is surrounded by a membrane
Although at one time a serious problem, beet leaf curl virus is of little economic
importance at present. The first symptoms it causes in sugar beet may be confused with
, but the subsequent intense leaf curling symptoms, its transmission by
and its characteristic bacilliform particles distinguish this
virus from all others infecting beet in Europe. However, P. quadratum
transmits a rickettsia-like organism, the cause of the beet latent rosette disease
described from Germany (Proeseler, 1980
- Coons, Stewart, Bockstahler & Schneider, Pl. Dis. Reptr 42: 502, 1958.
- Eisbein, Arch. Phytopath. PflSchutz 12: 299, 1976.
- Eisbein & Proll, Arch. Phytopath. PflSchutz 14: 81, 1978.
- Lee, Virology 34: 583, 1968.
- Peters, CMI/AAB Descr. Pl. Viruses No. 244, 6 pp., 1981.
- Proeseler, Phytopath. Z. 56: 191, 1966a.
- Proeseler, Phytopath. Z. 56: 213, 1966b.
- Proeseler, Arch. Phytopath. PflSchutz 14: 95, 1978a.
- Proeseler, NachrBl. PflSchutz DDR 32: 254, 1978b.
- Proeseler, in Vectors of Plant Pathogens, p. 97, ed. K. F. Harris & K. Maramorosch, New York: Academic Press, 1980.
- Schmutterer & Ehrhardt, Z. PflKrankh., PflPath., PflSchutz 73: 271, 1966.
- Wille, Arb. Biol. Reichsanst. Land-u. Forstw. 16: 115, 1928.
- Wille, Monogr. zum PflSchutz No 2, 116 pp., Berlin: Springer, 1929.
Young sugar beet (Beta vulgaris) leaf, systemically infected, showing vein clearing.
Infected sugar beet plant, showing leaf curl symptoms.
Chenopodium quinoa leaf showing vein clearing and deformation.
Adult male Piesma quadratum. Bar represents 1 mm. (Proeseler, 1966a).
Bacilliform particles in a thin section of root of infected fodder beet
(B. vulgaris) plant. Bar represents 100 nm. (Original electron micrograph by K. Eisbein.)