Pepper veinal mottle virus
A. A. Brunt
Glasshouse Crops Research Institute, Littlehampton, Sussex, England
R. H. Kenten
Rothamsted Experimental Station, Harpenden, Hertfordshire, England
- Described by Brunt & Kenten (1971).
- An RNA-containing virus with filamentous particles usually flexuous and
c. 770 x 12 nm, but under some conditions straight and c. 850 x
12 nm. It is readily sap-transmissible to a narrow range of hosts, and is
transmitted by aphids in the non-persistent manner. A member of the
Y group of viruses. Prevalent in Capsicum annuum and C. frutescens
Causes severe leaf chlorosis in Petunia hybrida
, and leaf mottling,
severe leaf distortion and considerable loss of yield in naturally infected
and C. frutescens
Reported only from Ghana.
Host Range and Symptomatology
Of 16 host species, 11 are members of the Solanaceae; 5 of 46 species tested,
from 3 of 17 other families, are also susceptible.
- Diagnostic species
- Capsicum annuum (pepper) cv. Long Red. Conspicuous systemic vein chlorosis
within 14-21 days, soon followed by interveinal chlorosis and general mottling
- Chenopodium amaranticolor. Local chlorotic and semi-necrotic lesions
c. 1-2 mm in diameter after 10-14 days (Fig.4); no systemic infection.
- Petunia hybrida cv. Rosy Morn. Faintly chlorotic local lesions,
followed by conspicuous systemic leaf mottling.
- Nicotiana clevelandii. Inoculated leaves usually symptomless;
systemically infected leaves become severely chlorotic within 21 days.
- Nicotiana megalosiphon. Severe systemic leaf chlorosis (Fig.3).
- Nicotiana tabacum cvs. Dutch A and White Burley. Circular chlorotic
lesions in inoculated leaves; no systemic infection.
- Propagation species
- Cultures may be maintained in Nicotiana clevelandii, N. megalosiphon
or Petunia hybrida, and all three species are good sources of inoculum
and of virus for purification.
- Assay species
- Chenopodium amaranticolor and C. quinoa are sensitive local
lesion assay hosts.
Transmission by Vectors
Transmitted efficiently in the non-persistent manner by Myzus persicae
and Aphis gossypii
. Virus can be acquired and inoculated in 2 min feeding
periods. Pepper veinal mottle virus resembles potato virus A
and potato virus Y
& Govier, 1971
) in aiding the aphid transmission of potato aucuba mosaic
(Brunt & Kenten, 1971
Transmission through Seed
Not seed-borne in Capsicum annuum, Nicotiana megalosiphon
(Brunt & Kenten, 1971
Transmission by Dodder
The virus is a good antigen; antisera react in tube precipitin tests to
produce flagellar precipitates at dilutions up to 1/8000 (Brunt & Kenten,
). The antiserum fails to react with intact virus in gel-diffusion tests,
but produces a single line of precipitate with disrupted virus.
The virus has many properties in common with potato Y
and allied viruses.
However, it is serologically unrelated to tobacco etch
, potato Y, turnip mosaic
and 11 other morphologically similar viruses (Brunt & Kenten, 1971
thus seems to be a distinct member of the potyvirus group
Stability in Sap
In Capsicum annuum
sap, the thermal inactivation point (10 min) is
55-60°C, dilution end-point 10-3
, and infectivity
is retained at 25°C for c
. 7-8 days. Sap lyophilized with 7% peptone
and 7% dextrose is still infective after 7 years in vacuo.
High molarity buffers prevent adsorption of virus to normal plant constituents.
Chloroform, ether or carbon tetrachloride clarify sap without deleterious effects,
but the virus particles are fragmented by n
-butanol. Yields of 12-15 mg
virus can be consistently obtained from 1 kg leaf tissue of Nicotiana
clevelandii, N. megalosiphon
or Petunia hybrida
by the following
procedure (Brunt & Kenten, 1971
). Homogenize systemically infected leaves
(1 g: 1 ml: 2 ml) in chloroform and 0.5 M borate at pH 7.8 containing 0.2%
2-mercaptoethanol; centrifuge at 10,000 g
for 10 min, and
precipitate virus from the aqueous phase by adding 50 g polyethylene glycol
(M. Wt 6000) to each litre of the extract and stirring for 1-2 hr at
2°C. Resuspend virus in 0.5 M borate at pH 7.8 for 2 hr, then clarify and
concentrate by differential centrifugation. The virus is further purified by
reprecipitation with polyethylene glycol followed by several cycles of
differential centrifugation, or by extracting and concentrating zones formed
during centrifugation in 10-40% sucrose density gradients. Purified virus
preparations in 0.05 M borate at pH 7.8 are mainly monodispersed with few
impurities, and remain infective and unaggregated for at least 1 month at
Properties of Particles
Sedimentation coefficient (s
): 155 S. No
accessory particles are found by analytical ultracentrifugation (Fig.5
immunoelectrophoresis the virus migrates as a single band slowly towards the
anode at a rate of 12.4 x 10-7
in 0.8% Ionagar in 0.033 M phosphate at pH 7.6.
Ultraviolet absorbance: maximum 260 nm, minimum 246 nm, with slight shoulder
at 290 nm.
A260/A246: 1.27±0.02, both after
correction for light-scattering (Brunt & Kenten, 1971).
Virus preparations contain numerous flexuous filamentous particles which,
in neutral phosphotungstate, measure c
. 12 x 770 nm (Brunt & Kenten,
). After exposure to 0.05 M MgCl2
, the particles become straighter
and measure c.
850 nm, but they can be restored to the shorter flexuous
form by removing Mg ions by dialysis against 0.02 M disodium ethylenediamine-tetraacetate
at pH 7.7 (Govier & Woods, 1971
). Most samples of sap from
systemically infected leaves contain flexuous particles c
. 12 x 750 nm
), but some from recently infected leaves contain either straight
filaments 12 x 850 nm (Fig.8
) or a mixture of straight and filamentous
particles. Particles mounted in uranyl formate show some surface structure
Particle CompositionRNA: c
. 6% of the particle weight (estimated from A260
probably single-stranded with molar percentages of nucleotides: G24; A23; C27; U26.
Protein: Probably a single protein species with subunits weighing c.
32,000-33,000 daltons (Brunt & Kenten, 1971).
Relations with Cells and Tissues
No amoeboid intracellular inclusions were detected in solanaceous hosts by
light microscopy, but sap of infected plants contains inclusion body material
(Brunt & Kenten, unpublished) similar to that induced by other members of the
potato Y group
(e.g. Hiebert et al., 1971
Of the eight adequately described viruses reported to infect Capsicum
and C. annuum
only tobacco etch
have particles morphologically similar to those of pepper veinal mottle
virus. The latter, however, is not serologically related to these two viruses,
and can also be readily distinguished from them by failing to infect Solanum
tuberosum, Lycopersicon esculentum
and Datura stramonium
, and causing
only local infection in Nicotiana tabacum
(Brunt & Kenten, 1971
Pepper veinal mottle virus resembles henbane mosaic,
bean yellow mosaic, and
several newly recognised viruses in having particles whose length depends on
their environment (Govier & Woods, 1971;
Brunt & Atkey, 1971).
- Brunt & Atkey, Rep. Glasshouse Crops Res. Inst. 1970: 152, 1971.
- Brunt & Kenten, Ann. appl. Biol. 69: 235, 1971.
- Govier & Woods, J. gen. Virol. 13: 127, 1971.
- Hiebert, Purcifull, Christie & Christie, Virology 43: 638, 1971.
- Kassanis & Govier, J. gen. Virol. 10: 99, 1971.
- Martyn, Phytopath. Pap. 9: 31, 1968.
Leaf distortion in naturally infected small red pepper.
Systemic chlorotic vein-banding in Capsicum annuum Long Red.
Systemic chlorosis in Nicotiana megalosiphon.
Local lesions in Chenopodium amaranticolor.
Schlieren pattern produced by a purified preparation after 8 min at
21,470 rev/min. Schlieren angle 30° Sedimentation is from left to right.
Particles mounted in uranyl formate. Bar represents 100 nm.
Particles from Petunia hybrida mounted in phosphotungstate;
shorter flexuous form. Bar represents 300 nm.
Particles from Capsicum annuum in phosphotungstate; longer
non-flexuous form. Bar represents 300 nm.