Pea seed-borne mosaic virus
R. O. Hampton
Agriculture Research Service, US Department of Agriculture, Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331, USA
G. I. Mink
Washington State University, Irrigated Agriculture Research and Extension Center, Prosser, Washington 99350, USA
- Disease described by Musil (1966) and Inouye (1967); virus partially
characterized by Knesek et al. (1974).
- Selected synonyms
- Pea leaf-rolling virus (Rev. appl. Mycol. 45: 2293)
- Pea fizzletop virus (Rev. Pl. Path. 49: 5m)
- Pea leafroll mosaic virus (Rev. Pl. Path. 49: 2012)
- Pea leaf-rolling mosaic virus (Rev. Pl. Path. 50: 372)
- An RNA-containing virus with filamentous particles c. 770 x 12 nm.
Transmissible by mechanical inoculation of sap, in the non-persistent manner
by aphids, and through seed. Disseminated primarily through infected pea seed
but transmissible to several other plant species. A typical, apparently distinct
member of the potyvirus group. Reported from the USA, Japan, Holland, and
Causes various degrees of stunting, downward rolling of leaflets, and a
transient clearing and swelling of leaf veins of most cultivars of Pisum
. Infected plants may produce distorted flowers, which often give
rise to small distorted pods. Ovule development in affected pods may be uneven,
with only one or two seeds produced. Seed coats may split as the seeds mature
Reported from the USA (Mink et al., 1969
; Hampton, 1969
; Stevenson &
), Japan (Inouye, 1967
), Czechoslovakia (Musil, 1966
), and the
Netherlands (Bos, 1970
). Possibly distributed world-wide, because seeds of many
cultivars known to be infected have been exchanged internationally.
Host Range and SymptomatologyPisum
cultivars are the main natural hosts, but the virus can infect
47 species in 12 dicotyledonous families (Aapola et al., 1974
non-leguminous hosts are infected without producing symptoms.
- Diagnostic species
- Pisum sativum (pea). Transient clearing and swelling of veins on the first
leaflets produced after infection, followed by downward rolling of leaflets and
tight curling of tendrils. Progressive shortening of internodes, often producing a
terminal rosette. These symptoms can be mistaken for physiological or genetic
disorders. Plants infected early or arising from infected seed produce no flowers
or a few distorted flowers and pods (Hampton, 1972) (Fig.1, Fig.2, Fig.4).
- Vicia faba (broad bean). Systemic dark and light-green zonal leaf
mottle, slight to moderate downward rolling of leaf margins. Distortions of leaf
shape associated with mottle patterns (Hampton & Baggett, 1970) (Fig.3).
- Chenopodium amaranticolor and C. quinoa. Necrotic local lesions
(Fig.5) and chlorotic local lesions, respectively. No systemic symptoms or infection.
- Propagation species
- Most Perfection-type pea cultivars are good sources of inoculum and of virus
- Assay species
- C. amaranticolor.
None described, but differences in particle length measurements (Musil, 1970
Hampton et al., 1974
) and in ultrastructural cytology (Hampton et al.,
) suggest that strains exist.
Transmission by Vectors
Transmissible in a non-persistent manner by the aphids Acyrthosiphon
pisum, Dactynotus escalanti, Macrosiphum euphorbiae, M. rosae, Myzus persicae, Ovatus
crataegarius, Rhopalosiphum padi,
(Aapola & Mink, 1973
), Aphis craccivora
and A. fabae
& Musil, 1967
), but not by Periphyllus lyropictus
(Aapola & Mink, 1973
). Aphids acquire and inoculate in 10-90 sec feeding
periods; no latent period is required (Gonzales & Hagedorn, 1970
Transmission through Seed
Transmitted through up to 30% of the seed from Pisum sativum
infected prior to flowering but not transmitted through seed from plants infected
after flowering begins (J. E. Knesek & G. I. Mink, unpublished data).
Commercial seed lots containing up to 90% infected seed were found (Knesek &
). Transmission was 8 times more frequent through seeds with split
seed-coats than through normal seeds (Stevenson & Hagedorn, 1970
transmission through seeds with split seed-coats, among 38 pea cultivars, varied
from 0 to 100% (Stevenson & Hagedorn, 1973
). Less than 1% of the seeds became
infected as the result of pollination with pollen from an infected parent plant
(Stevenson & Hagedorn, 1973
). Transmitted through a low percentage of seeds
of Vicia articulata, V. narbonensis
and V. pannonica.
The virus is a moderately good immunogen: antisera obtained from rabbits
given five intravenous injections of c
. 0.2 mg virus had homologous
titres of 1/1024 in microprecipitin tests (Knesek et al., 1974
virus reacts with antisera in ring interface tests and in gel-diffusion tests.
Chloroplast agglutination reactions have been obtained between sap of infected
pea tissue and some, but not all, antisera.
Isolates from the USA and Japan were found to be serologically related (Mink
et al., 1974
). Some antiserum preparations reacted to purified bean yellow
in controlled microprecipitin tests, but not in microslide
gel-diffusion tests. Relationships to other legume-infecting potyviruses not
Stability in Sap
Juice from pea leaf or root tissue is highly infective when initially prepared.
Extracts from roots remain infective for more than 96 h, whereas undiluted leaf
extracts become non-infective within 24 h at room temp. Leaf extracts diluted
or more remain infective for more than 96 h (Knesek et al.,
). The dilution end-point is between 10-3
Only traces of infectivity remain after 10 min at 55°C. Infectivity is lost
PurificationKnesek et al. (1974)
: Homogenize 18 g freshly harvested leaf or root
tissue in 180 ml freshly prepared buffer containing 0.01 M sodium
diethyldithiocarbamate (NaDIECA), 0.01 M cysteine-HCl, and (for leaf tissue only)
0.01 M ethylenediamine-tetraacetic acid (EDTA). Express juice through cheesecloth,
incubate for 1 h at 30°C, then emulsify for 30 min at 30°C with 0.5 vol
chloroform. Centrifuge the emulsion for 30 min at 3000 g
the upper phase and centrifuge for 1.5 h at 90,000 g
each pellet overnight in 4 ml cold distilled water adjusted to pH 7.0 with
0.005 M NaOH. Clarify suspension by centrifuging for 15 min at 10,000
. Layer 20 ml of the supernatant fluid in Beckman SW25 rotor tubes
over 10 ml 30%. sucrose containing 4% polyethylene glycol (PEG, M. Wt 6000) and
0.12 M NaCl. After 2 h at 24,000 rpm, resuspend the pellets overnight in 2.5 ml
2% sucrose containing 0.1% Igepon T73 at pH 7.0, and subject the virus to a
second cycle of centrifugation through sucrose/PEG. When centrifuged in rate
zonal density gradients the virus forms a single highly infective visible band.
This procedure yields 1 to 1.5 mg virus from 18 g fresh tissue.
Properties of Particles
Preparations usually contain one sedimenting component with a sedimentation
) of 154 S and buoyant density
in CsCl of 1.329 g/cm3
Absorbance at 260 nm (1 mg/ml, 1 cm light path): 2.5.
) are slightly flexuous filaments c
. 770 x 12 nm.
Some isolates appear highly susceptible to breakage unless fixed with 3.5%
glutaraldehyde (Hampton et al., 1974
Particle CompositionNucleic acid:
5.3 ± 1% of the particle weight. RNA, presumably
single-stranded. Molar percentage of nucleotides, G 22.8; A 44.0; C 17.6; U 15.6
(Knesek et al., 1974
Protein: About 94% of the particle weight. Subunit M.Wt 34,000 (Huttinga,
1975). Relative amino acid molar ratio:
Ala 3.3, Arg 2.5, Asx 4.7, Glx 4.9, Gly 2.7, His 1.0, Iso 1.8, Leu 2.2, Lys 1.5,
Met 1.9, Phe 1.1, Pro 1.4, Ser 2.2, Thr 2.0, Tyr 1.2, Val 2.4, Cys and Try not
determined (Knesek et al., 1974).
Relations with Cells and Tissues
Most isolates induce pinwheel inclusions (Inouye, 1971
) in the cytoplasm of
mesophyll cells of Pisum sativum
and Vicia faba
et al., 1973
). Less common isolates induce tonoplast aggregates or dense
bodies and laminated aggregates. One isolate characterized by induction of
tonoplast aggregates also induced formation of convoluted endoplasmic reticulum
(Hampton et al., 1973
). Masses of virus-like particles occur
in pea root parenchyma cytoplasm.
The following features distinguish other pea viruses from pea seed-borne
mosaic virus. Pea mosaic virus
(Doolittle & Jones, 1925
), although a
, typically induces striking mosaic patterns in leaves of infected
plants, with little stunting, and is rarely seed-borne. Pea early browning
(Bos & Van der Want, 1962
) is a tobravirus, induces stem, petiole,
leaf and pod necrosis, and is transmitted in nature both by seed and by
spp.). False pea leaf roll virus (Thottappilly
& Schmutterer, 1968
) (no report on particle morphology) induces leaf rolling
as well as chlorotic and necrotic spots and vein necrosis of leaves and is
reportedly seed-borne, soil-borne and aphid-borne (Myzus persicae
Bean leaf roll virus
(Quantz & Volk, 1954
) (pea leaf roll virus, pea
tip-yellowing virus, pea top yellows virus, pea yellows virus) (no report on
particle morphology) induces various degrees of plant stunting, erect plant
habit, sieve-tube necrosis, and chlorosis of apical leaves, is transmissible
by aphids (Myzus persicae
), but not mechanically or through the seeds
of pea. The disease it induces in pea resembles that caused in Australia by
subterranean clover stunt virus (Smith, 1966
Pea seed-borne mosaic virus has appeared abruptly in pea breeding programs in
the USA and elsewhere. This appearance is attributable to the international
exchange of infected seed-lots, particularly for breeding. Symptoms induced by
this virus have been mistaken by breeders as plant variants or mild physiological
disorders. Symptoms may be mild, are unlike classical virus symptoms, and tend
to fade as plants approach flowering (Hampton, 1972). The disease seriously
threatens pea production, jeopardizes international shipments of pea seed, and
may exist unrecognised in breeding lines from which it may be spread to healthy
lines by aphid vectors.
Virus-infected seeds may or may not have split seed-coats. A low incidence of
growth-cracking is normal for the seeds of many pea cultivars. Drought during
seed development and other factors may affect the proportion of split seed-coats
produced by virus-free or infected plants.
The virus may be present without inducing symptoms in 5 to 10% of the plants
from infected seed-lots (Hampton, 1972). Moreover, the virus may not be
detectable in symptomless plants by assay on C. amaranticolor until 8
to 10 weeks after emergence. Most infected seed, however, gives rise to
seedlings showing some stunting, leaf-roll and vein-swelling.
- Aapola & Mink, Pl. Dis. Reptr 57: 552, 1973.
- Aapola, Knesek & Mink, Phytopathology 64: 1003, 1974.
- Bos, Neth. J. Pl. Path. 76: 8, 1970.
- Bos & van der Want, Tijdschr. PlZiekt. 68: 368, 1962.
- Doolittle & Jones, Phytopathology 15: 763, 1925.
- Gonzales & Hagedorn, Phytopathology 60: 1293, 1970.
- Hampton, Phytopathology 59: 1029, 1969.
- Hampton, Phytopathology 62: 268, 1972.
- Hampton & Baggett, Pl. Dis. Reptr 54: 355, 1970.
- Hampton, Phillips, Knesek & Mink, Archiv. ges. Virusforsch. 42: 242, 1973.
- Hampton, Knesek & Mink, Phytopathology 64: 1358, 1974.
- Huttinga, Neth. J. Pl. Path. 81: 58, 1975.
- Inouye, Ann. phytopath. Soc. Japan 33: 38, 1967.
- Inouye, Nogaku Kenkyu 53: 189, 1971.
- Knesek & Mink, Pl. Dis. Reptr 54: 497, 1970.
- Knesek, Mink & Hampton, Phytopathology 64: 1076, 1974.
- Kvicala & Musil, Biológia Bratisl. 22: 10, 1967.
- Mink, Kraft, Knesek & Jafri, Phytopathology 59: 1342, 1969.
- Mink, Inouye, Hampton & Knesek, Phytopathology 64: 569, 1974.
- Musil, Biológia Bratisl. 21: 133, 1966.
- Musil, Biológia Bratisl. 25: 379, 1970.
- Quantz & Volk, NachrBl. dt. PflSchutzdienst. Stuttg. 12: 177, 1954.
- Smith, Aust J. agric. Res. 17: 875, 1966.
- Stevenson & Hagedorn, Phytopathology 59: 1051, 1969.
- Stevenson & Hagedorn, Phytopathology 60: 1148, 1970.
- Stevenson & Hagedorn, Pl. Dis. Reptr 57: 248, 1973.
- Thottappilly & Schmutterer, Z. PflKrankh. PflPath. PflSchutz 75: 1, 1968.
Appearance of Perfection-type pea with severe leaf roll symptoms
(left), moderate leaf roll (centre); healthy plant (right).
Note apparent sparsity of foliage caused by reduced leaf size and leaf roll.
Close-up of severely affected pea plant, showing downward rolling of
lateral leaf margins, an abortive phyllody-type flower (AF), and a young
distorted pod (P). Inset: seeds from infected plants, showing (above)
characteristic split seed-coats (growth cracking), (below) seeds from
Characteristic symptoms induced in broad bean (Vicia faba),
including zonal-mottle, downward rolling and distortions of leaf margins.
Healthy leaf at bottom.
Incomplete and uneven ovule development in pod from an infected pea
plant (bottom) and complete development in pod from healthy plant
Characteristic lesions induced in leaves of Chenopodium
amaranticolor, with necrotic centres and translucent haloes.
Virus particles negatively stained in sodium phosphotungstate. Bar
represents 250 nm.
Electron micrograph of a thin section of infected pea mesophyll
parenchyma cell, showing aggregates of virus-like particles inside
tonoplast (TA), convoluted endoplasmic reticulum (ERc), and a tangential
section through pinwheel configurations (PW). Bar
represents 250 nm.
Electron micrograph of a thin section of the same infected pea mesophyll
parenchyma cell as in Fig.7, showing transverse
section through a pinwheel.
Electron micrograph of a thin section through an infected pea root
cortical parenchyma cell, showing a mass of virus-like particles (V) within the
ground cytoplasm (C). CW, cell wall. Bar represents 250 nm.
Histogram of virus particle lengths, showing modal length of 770 nm.