Lily symptomless virus
T. C. Allen
Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331, USA
- Described by Brierley & Smith (1944) and Allen & McWhorter (1966).
- Selected synonyms
- Lily curl stripe virus (Rev. appl. Mycol. 46, 12v)
- Lily virus (Allen, 1971)
- Marmor mite (Rev. appl. Mycol. 28: 514)
- A virus with elongated slightly flexuous filaments c. 640 nm long and
18 nm in diameter, restricted to members of the Liliaceae. Probably transmitted by
Myzus persicae in a non-persistent manner; also transmissible by leaf unions
and by inoculation of sap. Widely distributed in commercial stocks of lilies.
Causes curl-stripe (and basal stripe) in lilies under some environmental
conditions. Causes necrotic fleck disease in lilies when associated with
. Causes brown rings in bulbs of Lilium
and streak mottle on leaves of L. speciosum
varieties when associated with
tulip breaking virus
(Asjes, de Vos & van Slogteren, 1973
Probably occurs wherever lilies are grown.
Host Range and Symptomatology
Host range is restricted to the Liliaceae. All host species are infected
systemically but they differ in susceptibility. Sap-transmissible. Also
transmissible by leaf unions (McWhorter & Allen, 1964
- Diagnostic species
- Lilium longiflorum seedlings previously infected with cucumber mosaic
virus develop necrotic flecks. Characteristic flecks of various sizes occur
about 3 weeks after inoculation. They are parallel to the leaf veins, and are
chlorotic at first, later becoming grey-brown and necrotic (Brierley &
Smith, 1944) (Fig.1).
- L. longiflorum seedlings inoculated with lily symptomless virus alone
and grown at temperatures less than 15.5°C develop curl-stripe
(characteristic white striping and extreme twisting of leaves) about 60 to 90
days after inoculation (McWhorter & Allen, 1967) (Fig.2).
- Propagation species
- L. longiflorum Ace is suitable for maintaining cultures and is a good
source of virus for purification.
- Assay species
- L. longiflorum previously inoculated with cucumber mosaic virus,
Tulipa gesneriana cvs. Clara Butt and Rose Copland. Dark streaks that
are more distinct on the outside than on the inside occur along the veins of
the petals of Rose Copland. This differs from the typical colour breaking
incited by tulip breaking virus (van Slogteren, personal communication). All
are systemic assay hosts.
Transmission by Vectors
A virus with particles about 650 nm long, which was probably lily
symptomless virus, was transmitted in the non-persistent manner by the aphid
(Mowat & Stefanac, 1972
). However, Brierley &
reported persistent transmission by Aphis gossypii
Transmission by Dodder
Antiserum from a rabbit injected intravenously with clarified sap from
infected lilies had a titre of 1/1280 in tube precipitin tests (van Slogteren
& de Vos, 1966
). A rabbit receiving three intravenous injections at weekly
intervals followed by two intramuscular injections of partially purified virus
from lilies with curl-stripe symptoms developed an antiserum titre of 1/1024
(T. C. Allen, unpublished). Tube or micro-precipitin tests in which antisera
form flocculent precipitates, are useful with clarified sap or partially purified
Properties and particle morphology place the virus in the carlavirus group
The virus reacted positively with antisera prepared against chrysanthemum B
, potato S
, carnation latent
and passiflora latent viruses, Antiserum to
lily symptomless virus reacted with partially purified (about 10 times
concentrated) suspensions of chrysanthemum B, potato M and potato S viruses
(van Slogteren & de Vos, personal communication).
Stability in Sap
Two methods have been described:
1. (Civerolo, Semancik & Weathers, 1968). Homogenize frozen leaf tissue 1:2
(w/v) in 0.25 M potassium phosphate buffer, pH 7.5, containing 0.002 M
MgSO4, 0.1% thioglycollic acid, and 10-15 ml 1% bentonite
solution/100 ml of buffer solution. Express homogenate through cheesecloth and
centrifuge at 2000 g for 5 min. Add additional 1% bentonite
solution at 1-5 ml/100 ml extract and clarify the suspension by low speed
centrifugation until the supernatant fluid is straw- coloured. Centrifuge the
supernatant fluid, first at 9600 g for 10 min then at 94,000
g for 2 hr. Resuspend the final pellets in 0.1 M phosphate
buffer, pH 7.0. Perform all operations at 4°C. When centrifuged in sucrose
density gradients, the virus gives a single light-scattering band.
2. (C. J. Asjes, unpublished). Homogenize leaves in 0.067 M phosphate buffer,
pH 7.2, +0.1% thioglycollic acid, squeeze through cheesecloth, and freeze the
extract at -20°C for one day or longer. Thaw overnight, add an equal volume
of chloroform. Stir occasionally for 30 min and centrifuge for 10 min at 1000
g. The resulting extract is ultracentrifuged for 2 hr at 90,000
g. The pellet is resuspended in phosphate buffer and centrifuged
for 10 min at 1000 g.
Properties of Particles
Sedimentation coefficient (s20,w
) at infinite dilution:
about 172 S.
A260/A280: 1.20-1.43 (Civerolo et al., 1968).
Particles are elongated, slightly flexuous rods, c.
640 nm long and
17-18 nm in diameter (Fig.3
). Particle centre is densely stained (Fig.5
When mounted in 2% sodium phosphotungstate or 1% uranyl acetate for electron
microscopy, the particles contrast well; the electron microscope is therefore
a useful aid in diagnosing infection with this virus (Civerolo et al.,
; Lyons & Allen, 1969
Nucleic acid is about 8.3% of particle weight (Civerolo, 1967
Relations with Cells and Tissues
All tissues are infected except, possibly, meristematic regions. Leaf
tissues tend to yield more particles than root or stem tissue. Thin section
studies have shown that the virus-like particles associated with the disease
occur in the cytoplasm (Fig.6
). No pinwheels or inclusion bodies have been
observed (Allen & Lyons, 1969
; Lyons & Allen, 1969
The name lily symptomless virus is perhaps unfortunate because other lily
viruses can sometimes infect lilies symptomlessly and lily symptomless virus
itself causes symptoms in lilies under some environmental conditions. The 650
nm virus described here is thought to be the lily symptomless virus described
by Brierley & Smith (1944)
because it causes necrotic fleck disease in
in mixed infections with cucumber mosaic virus
main cause for doubt is that, whereas the virus described by Brierley &
Smith was transmitted in a persistent manner by Aphis gossypii,
(Mowat & Stefanac, 1972
) suggests that the 650 nm virus, like other members
of the carlavirus group
, is transmitted in the non-persistent manner by aphids.
However, at present, it seems best to retain the name lily symptomless virus.
Another virus, lily mottle virus (= tulip breaking virus), often occurs in
necrotic fleck-diseased L. longiflorum but apparently is not involved
in the disease (Brierley & Smith, 1944). In sections of plants showing mottle
symptoms as well as necrotic fleck, 750 nm virus particles and pinwheel
inclusions characteristic of tulip breaking virus can be found (Allen, 1971).
- Allen, Lily Yb., N. Am. Lily Soc. 24: 29, 1971.
- Allen & McWhorter, Phytopathology 56: 869, 1966.
- Allen & Lyons, Phytopathology 59: 1318, 1969.
- Brierley & Smith, Phytopathology 34: 529, 1944.
- Asjes, de Vos & van Slogteren, Neth. J. Pl. Path. 79: 23, 1973.
- Civerolo, Doctoral Dissertation, Univ. Calif., Riverside, 1967.
- Civerolo, Semancik & Weathers, Phytopathology 58: 1481, 1968.
- Lyons & Allen, J. Ultrastruct. Res. 27: 198, 1969.
- McWhorter & Allen, Nature, Lond. 204: 604, 1964.
- McWhorter & Allen, in Easter Lilies, p. 111, Eds. D. C. Kiplinger & R. W. Langhans, The New York and Ohio Lily Schools, 1967.
- Mowat & Stefanac, Lily Yb., N. Am. Lily Soc. 33: 251, 1972.
- van Slogteren & de Vos, in Viruses of Plants, p. 320, Eds. A. B. R. Beemster & Jeanne Dijkstra, North-Holland, Amsterdam, 1966.
Necrotic fleck symptoms in Lilium longiflorum caused by mixed
infection with lily symptomless virus and cucumber mosaic virus (courtesy F. P.
Curl-stripe symptoms in L. longiflorum caused by infection with
lily symptomless virus alone (courtesy F. P. McWhorter).
Metal-shadowed preparation of virus particles extracted from leaves
of Ace lily with curl-stripe symptoms. Bar represents 200 nm.
Virus particle in sodium phosphotungstate-treated preparation from
leaves of Ace lily with necrotic fleck disease. Bar represents 100 nm.
Cross-section of virus particles in situ. Stained with osmium
tetroxide, uranyl acetate and lead citrate. Bar represents 50 nm.
Section of root cell from a necrotic fleck-diseased Ace lily, showing
virus particle aggregates in cross, oblique and longitudinal section. Bar
represents 200 nm.