Ginger chlorotic fleck virus
J. E. Thomas
Agricultural Research Laboratories, Department of Primary Industries, Indooroopilly, Queensland 4068, Australia
A virus with isometric particles c. 30 nm in diameter which sediment as a
and contain one major species of ssRNA. The virus is mechanically transmitted to ginger,
known host. No vector is known. Detected in Australia in some imported lines of ginger.
Causes chlorotic flecks on the leaves of infected ginger
No obvious symptoms occur on the rhizomes. The effect on yield has not been studied.
The virus is
transmitted through the rhizome of infected plants.
Detected in ginger introduced to Australia from India, Malaysia, Mauritius and Thailand. The
imported material was grown in isolation in experimental plots and has since been destroyed.
has not been found in Australia in surveys of commercial ginger plantings
Host Range and Symptomatology
Transmitted by mechanical inoculation to ginger, the only known host
- Zingiber officinale (ginger). The leaves of infected plants show chlorotic flecks,
1-10 mm long,
parallel to and usually centred on the veins
Symptoms first appear 3-4 weeks after inoculation
in young leaves and persist in these and all subsequently formed leaves.
Propagation and assay species
- Zingiber officinale; no local lesion assay host is known.
All isolates studied appear serologically identical.
Transmission by Vectors
Vector not known. Not transmitted by the aphids Myzus persicae, Pentalonia nigronervosa,
or R. padi
Transmission through Seed
Moderately immunogenic; an antiserum prepared in a rabbit had a gel diffusion titre of 1/512
Single lines of precipitate are obtained in gel diffusion tests against either
purified virus or infective sap. Immunosorbent electron microscopy and a
plate-trapped antigen form
of ELISA are useful for virus detection.
Ginger chlorotic fleck virus has many properties in common with viruses in the
including 30 nm-diameter particles which sediment as a single component
a predominant ssRNA species of M. Wt 1.5 x 106
, salt-labile particles and
a limited host
range. However some properties, including banding behaviour in CsCl and
gradients, instability in potassium phosphotungstate and migration as two
are atypical of this group. The virus is serologically unrelated to several members and
of the sobemovirus group, including
lucerne transient streak
solanum nodiflorum mottle
southern bean mosaic
velvet tobacco mottle
Additionally, no serological reactions were detected with antiserum to the following viruses
cucumber fruit streak
hibiscus chlorotic ringspot
narcissus tip necrosis
pelargonium ring pattern,
pelargonium vein netting,
red clover necrotic mosaic
Stability in Sap
Homogenize each 100 g fresh ginger leaves in 400-500 ml 0.5 M sodium citrate buffer,
containing 0.5% (w/v) Na2
. Filter the extract through
stir with 25 ml chloroform for 10 min. Break the emulsion by centrifugation at
for 10 min. Collect the aqueous phase and subject to two cycles of differential
for 60 min and 8000 g
for 10 min,
resuspending the pellets each
time in 50 mM sodium phosphate buffer, pH 7.0, containing 1 mM EDTA. Purify further
in 10-40% linear sucrose density gradients. Yields are usually 50-90 mg/kg tissue
Similar yields are obtained when leaf tissue is homogenized in 0.25 M sodium citrate buffer, pH 6.5,
containing 0.25% (w/v) Na2SO3, and clarified by adding
butan-1-ol to 5% (v/v),
leaving all other steps as previously described. Yields are greatly reduced when leaves
are frozen at
-20°C before use.
Properties of Particles
The particles sediment as a single component
Sedimentation coefficient, (s20,w): 111 S.
Electrophoretic mobility: migrates towards the anode as two approximately
Absorbance at 260 nm (A260 (0.1%, 1 cm)): 5.6.
A260/A280: 1.58 (not corrected for light-scattering).
Buoyant density in CsCl (g/cm3): 1.355 (particles fixed in glutaraldehyde).
Buoyant density in Cs2SO4 (g/cm3): 1.297 (at pH 4.9)
(at pH 6.9).
Stability: particles are stable in 10 mM Tris, 10 mM NaCl, pH 8.25, but unstable
in 10 mM Tris,
10 mM EDTA, 1 M NaCl, pH 8.25. Neutral potassium phosphotungstate and
caesium chloride solutions
also cause disruption of the particles
Particles are disrupted by mounting in neutral potassium phosphotungstate.
In ammonium molybdate
or uranyl acetate
they are isometric, about 30 nm in diameter and have obvious
hexagonal outlines. A proportion are penetrated by the negative stain
Particle CompositionNucleic acid:
RNA, single-stranded, comprising c.
20% of particle weight
from the buoyant density in CsCl). Polyacrylamide gel electrophoresis under
indicates a M. Wt for the main component of 1.50 x 106
. Minor components of
M. Wt 0.59 x
and 0.14 x 106
are also detected in varying amounts
Protein: A predominant protein species of M. Wt 29.0 x 103,
SDS-polyacrylamide gel electrophoresis. A minor species of M. Wt 27.3 x 103
Relations with Cells and Tissues
Randomly distributed virus-like particles and membrane-bound vesicles
have been observed in the
cytoplasm of mesophyll cells from infected ginger
(J. E. Thomas & D. H. Gowanlock, unpublished
Few virus diseases of ginger have been reported.
Wheat mosaic streak virus
described from India
(Ganguly & Raychaudhuri, 1971
Basu & Raychaudhuri, 1972
differs in infecting wheat (
) and in being transmitted by the aphids
Cucumber mosaic virus
(ginger mosaic virus;
differs in particle properties,
host range and aphid transmissibility, and is serologically distinct.
A mosaic disease of ginger from
India, described by
Nambiar & Sarma (1974)
has similar leaf symptoms but has not been sufficiently
characterized to allow a detailed comparison.
Ginger chlorotic fleck virus is readily identified by serological tests.
- Basu & Raychaudhuri, Indian J. Ent. 34: 115, 1972.
- Ganguly & Raychaudhuri, Phytopath. Z. 70: 11, 1971.
- Matthews, Intervirology 17: 1, 1982.
- Nambiar & Sarma, Arecanut and Spices Bull. 6: 3, 1974.
- So, Korean J. Pl. Prot. 19: 67, 1980.
- Thomas, Ann. appl. Biol. 108: 43, 1986.
Figs 1, 2 and 4 from Thomas (1986).
Chlorotic fleck symptoms in infected ginger leaf (below); healthy leaf
Purified particles mounted in ammonium molybdate. Bar represents 100 nm.
Particles mounted in uranyl acetate. Bar represents 100 nm.
Schlieren pattern of a purified preparation, after centrifuging for 16 min at