Carnation latent virus
C. Wetter
Botanisches Institut, Universität des Saarlandes, 66 Saarbrücken, Germany
Contents
Introduction
Described by
Kassanis (1954).
An RNA-containing virus with straight to slightly curved filamentous particles
c. 650 x 12 nm. Transmissible by inoculation of sap and by aphids in the
non-persistent manner.
Main Diseases
Causes few or no symptoms in carnation
(Dianthus caryophyllus).Geographical Distribution
Found occasionally in cultivated carnation plants in UK and continental Europe.
Host Range and Symptomatology
No extensive studies on host range and symptomatology. Difficult to transmit
from carnation to other species because of inhibitors in the sap. The virus can
infect a number of plants outside the family Caryophyllaceae such as
Nicotiana
clevelandii, in which it multiplies without causing symptoms (M. Hollings,
pers. comm.).
- Diagnostic species
- Chenopodium amaranticolor.
Small chlorotic local lesions in inoculated
leaves; systemic mottle.
- Chenopodium quinoa. Small yellowish spots in inoculated leaves; systemic
interveinal mottle and leaf dwarfing (Fig.1).
- Propagation species
- Dianthus barbatus
is a suitable source of virus for purification.
- Assay species
- Chenopodium amaranticolor
or C. quinoa.
Strains
None reported.
Transmission by Vectors
Transmissible in the non-persistent manner by the aphid
Myzus persicae
to carnation, sweet william and sugar beet (
Kassanis, 1955).
Transmission through Seed
None reported.
Transmission by Dodder
None reported.
Serology
Antisera with titres of 1/32,000 were prepared (
Wetter, 1960) using purified
virus preparations. The precipitate in precipitin tube tests is flagellar. Double
diffusion tests in agar gel can be used, but a high concentration of antigen is
necessary (
Wetter, 1967). No low-molecular weight antigen has been observed.
Relationships
The virus belongs to the potato virus S group. It is distantly serologically
related to the following viruses:
potato S (
Kassanis, 1955;
1956)
potato M
(
Bagnall, Wetter & Larson, 1959),
chrysanthemum B (
Hakkaart, Van Slogteren
& De Vos, 1962), passiflora latent (
Brandes & Wetter, 1963), cactus 2
(
Brandes & Wetter, 1963) and
red clover vein mosaic (
Wetter, 1967).
Stability in Sap
In carnation sap, the thermal inactivation point (10 min) is 60-65°C,
dilution end-point 10
-3-10
-4 and infectivity is retained
in carnation sap at 20°C for 2-3 days.
Purification
(
Wetter & Paul, 1961). Extract sap from leaf tissue of
Dianthus
barbatus, filter and add ascorbic acid (to 0.2% w/v) and sodium sulphite
(to 0.2% w/v). Shake sap with an equal volume of diethylether. Centrifuge at
low speed. Shake clarified aqueous phase with an equal volume of carbon
tetrachloride. Centrifuge at low speed and again retain aqueous phase. Adjust
to pH 7.0 with 0.5 M phosphate buffer and add
n-butanol to 8% (v/v).
Keep at 4°C overnight. Shake with an equal volume of carbon tetrachloride
and centrifuge at low speed, retaining aqueous phase. Sediment the virus by high
speed centrifugation, resuspending it in 0.2 M borate buffer. Dialyse against
0.02 M borate buffer at 4°C. Concentrate by three cycles of differential
centrifugation. Infected leaves of
Dianthus barbatus may yield 40-60 mg
virus per litre of expressed sap.
Properties of Particles
(
Paul & Wetter, 1964). Sedimentation coefficient
(
s20,w): 167 S. No accessory viral components are
found by ultracentrifugation but aggregates may occur.
Diffusion coefficient: c. 0.24 x 10-7cm2/sec.
Molecular weight: c. 6 x 107.
Partial specific volume: 0.72 cm3/g.
Absorbance at 260 nm (1 mg/ml, 1 cm light path): 2.1.
A260/A280: 1.37;
Amax/Amin: 1.23.
Particle Structure
Particles are straight to slightly curved filaments
c. 650 x 12 nm
(
Brandes et al., 1959) with a central channel (
Fig.2,
Fig.3). Particles
are helically constructed with a basic helix of pitch 3.3 nm and about 12
subunits per turn (
Varma et al., 1968).
Particle Composition
14.6% of particle weight is nitrogen, 0.5% phosphorus. RNA is 6% of particle
weight (
Paul & Wetter, 1964).
Relations with Cells and Tissues
No reports.
Notes
No differential host has been found in which carnation latent virus can
be separated from other carnation viruses. It may be transmitted to healthy
Dianthus barbatus plants by the aphid
Myzus persicae which is
also a vector of
carnation vein mottle virus. It is possible to eliminate the
latter from sap containing both viruses by heating the inoculum for 10 min at
60°C (
Kassanis, 1955).
References
- Bagnall, Wetter & Larson, Phytopathology 49: 435, 1959.
- Brandes & Wetter, Phytopath. Z. 49: 61, 1963.
- Brandes, Wetter, Bagnall & Larson, Phytopathology 49: 443, 1959.
- Hakkaart, Van Slogteren & De Vos, Tijdschr. PlZiekt. 63: 126, 1962.
- Kassanis, Nature, Lond. 173: 1097, 1954.
- Kassanis, Ann. appl. Biol. 43: 103, 1955.
- Kassanis, J. gen. Microbiol. 15: 620, 1956.
- Paul & Wetter, Phytopath. Z. 49: 401, 1964.
- Varma, Gibbs, Woods & Finch, J. gen. Virol. 2: 107, 1968.
- Wetter, Arch. Mikrobiol. 37: 278, 1960.
- Wetter, Z. Naturf. Ser. B 22: 1008, 1967.
- Wetter & Paul, Phytopath.Z. 43: 207, 1961.
Acknowledgements
The support of the ‘Deutsche Forschungsgemeinschaft’ is gratefully
acknowledged.
Chenopodium quinoa showing (left) healthy leaf,
(right) infected leaves showing systemic symptoms of interveinal mottle
and leaf dwarfing. (Courtesy of Dr M. Hollings, Glasshouse Crops Research Institute, UK.)
Virus particles from a leaf dip preparation in phosphotungstate. Bar
represents 200 nm.
Virus particles from a partially purified preparation in
phosphotungstate. Bar represents 200 nm.
