Maize streak virus
K. R. Bock
Overseas Development Administration, Crop Virology Project, East African Agriculture and Forestry Research Organisation, Nairobi, Kenya
- Described by Storey (1925) and Bock, Guthrie & Woods (1974).
- Selected synonyms
- Maize streak virus A (Rev. appl. Mycol. 29: 614)
- Sugarcane streak virus (Rev. appl. Mycol. 4: 442)
- A small isometric virus, probably containing RNA, with particles
c. 20 nm in diameter, usually occurring in pairs measuring 30 x 20 nm.
Transmitted by leafhoppers (Cicadulina spp.) in the persistent manner
but not by inoculation of sap. Host range is apparently confined to the
Gramineae. The virus occurs throughout Africa south of the Sahara and in
Causes severe streak disease of maize (Zea mays)
), sugarcane (Saccharum officinarum
), millet (Eleusine
and many grasses (Fig.3
), and stunt of wheat (Triticum
Maize streak virus occurs in Africa south of the Sahara, and in Mauritius
and Madagascar; it has been reported from India and probably occurs elsewhere
in southeast Asia. It does not occur in the New World.
Host Range and Symptomatology
All known hosts are in the Gramineae, among which many species can be
infected. In Africa, streak disease has been recorded in species in the tribes
Andropogoneae (Cymbopogon, Imperata, Saccharum, Rottboellia),
(Dactyloctenium, Diplachne, Eleusine, Eragrostis, Leptochloa, Setaria),
and Avenae (Avena)
& McLean, 1930
; McLean, 1947
Transmission experiments must be done with leafhopper vectors because the virus
is not manually transmissible.
- Diagnostic species
- For maize (type) strain: Zea mays (maize). First symptoms in young
seedlings appear 3-7 days after inoculation as almost circular pale spots
0.5-2 mm diameter in the lowest exposed portions of the youngest leaves (Fig.4).
When the disease is fully developed the plants show narrow veinal streaks which
range from a few mm to several cm long, from 0.5-1 mm wide and frequently fuse
- For other strains: Several strains do not infect maize; diagnosis
must include transmission by Cicadulina to the host species under study,
and evidence on particle morphology and serology.
- Propagation and assay species
- Cultures of the various strains are best maintained and assayed in their
own specific host: e.g. the maize (type) strain in maize; the sugarcane strain in
susceptible varieties of Saccharum; the guinea grass strain in
Panicum maximum. No host is known that produces local lesions, and
assays must be done by recording the proportion of test plants that become
infected following inoculation by means of the leafhopper vector.
- Leafhoppers can be rendered viruliferous by feeding through membranes
on crude sap or purified preparations and by intrahaemocoelic injection.
Although maize streak virus apparently has a wide host range among
African species of Gramineae, the strains show considerable host adaptation
(Bock et al., 1974
). McLean (1947)
distinguished several forms of
streak-producing viruses on host range and reaction and on speed of symptom
development in maize: a severe (A) and a mild (B) form from maize; a form
from sugar-cane (Uba-virus) that afforded no protection in maize against
either the A or B viruses; and three forms from wild grasses (Sporobolus,
viruses), transmissible to maize but not
Bock et al. (1974, and unpublished) have shown that four streak-disease
viruses (those occurring naturally in maize, sugarcane, Panicum and
Eleusine) have identical particle morphology and are serologically related
though distinguishable. In Africa, it seems that some strains which were
adapted to wild hosts, such as those occurring naturally in Eleusine
and Sporobolus, proved highly pathogenic to the exotic maize.
Transmission by Vectors
The known vectors of maize streak virus are confined to the genus
They are C. mbila, C. storeyi, C. bipunctella zeae,
and C. parazeae
Storey, Howland &
Storey (1925; 1928;
1939) studied vector transmission in
great detail. The virus may be acquired in less than 1 h (minimum acquisition
time 15 sec) and may be inoculated in 5 min; latent period in the vector is
6-12 h at 30°C, which coincides with the first appearance of the virus
in the body fluids. Storey suggested that the vector remained viruliferous
for life, but experimental proof that the virus replicates within the vector
All five nymphal instars are able to acquire and transmit the virus; it is
retained during moulting but is not transmitted through the egg. Races that
are active (able to transmit) and inactive have been found for
four of the five vector species of Cicadulina (mbila, storeyi, bipunctella
zeae and latens); the gut wall of inactive races is impermeable to
passage of the virus but inactive races are rendered active by injecting virus
into the abdomen or by puncturing the gut wall. The ability to transmit is
inherited as a simple dominant gene linked with sex. Employing conventional
notation (A = major gene for activity, a for inactivity), the
constitutions are active males (AX) (Y); inactive males, (aX) (Y); active
females, (AX) (AX) or (AX) (aX); and inactive females, (aX) (aX). Individual
insects of an active race are not equally efficient; there is evidence that a
second gene, not sex-linked, modifies the effect of the major gene for activity.
Transmission through Seed
Not seed-transmitted in maize.
Transmission by Dodder
Maize streak virus is moderately to strongly immunogenic; Bock
et al. (1974)
obtained an antiserum with titres of 1/256 and 1/1024
in gel-diffusion and tube precipitin tests respectively.
Strains of the virus from maize, sugarcane, guinea grass and millet are
identical in particle morphology and are serologically related though
distinguishable (Bock et al., 1974
). The millet and sugarcane strains
are closely related to the maize strain, the guinea grass strain more
distantly. Strains differ greatly in host range and virulence; even serologically
closely related strains do not cross-protect (Storey & McLean, 1930
; Bock et al., 1974
). For example, the maize (type) strain induces
a mild transient streak in sugarcane; the sugarcane strain causes a mild
permanent infection in maize. Neither of these strains infects guinea grass,
nor does the guinea grass strain infect maize or sugarcane.
Stability in Sap
Studied by allowing vectors to feed through membranes on crude sap
containing the type (maize) strain and transferring them to maize seedlings.
Thermal inactivation point is not less than 60°C; dilution end-point not
less than 1/1000; longevity at room temperature not less than 24 h (K. R.
Bock & E. J. Guthrie, unpublished data).
The different virus strains may be purified satisfactorily from their
preferred hosts (Bock et al., 1974
). Homogenize 100 g infected leaf
tissue in 200 ml 0.01 M phosphate buffer containing 0.1 % thioglycollic acid,
pH 3.9-4.1. Clarify with n
-butanol (7 ml/100 ml extract), concentrate by
ultracentrifugation, and resuspend the virus in 0.01 M phosphate, pH 7.7.
Properties of Particles
(Bock et al., 1974
). Sedimentation coefficent,
: 76 S for paired and 54 S for
Particles are isometric, 20 nm in diameter, but are usually paired
(30 x 20 nm) (Fig.5
). The ratios of paired to single particles was
approximately 8:1 (chloroform preparations) or 3:1 (n
preparations). In paired particles, individuals seem to be 5-sided, whereas
single particles appear hexagonal (Bock et al., 1974
Tests using acridine orange staining (Cowan & Graves, 1968
that the nucleic acid is single-stranded, probably RNA (Bock et al.,
Relations with Cells and TissuesStorey (1928
) found that virus was restricted to chlorotic areas
of the leaf, and was not acquired from mesophyll or phloem of green areas.
Infection depends on the stylet of the vector penetrating the phloem of the
plants inoculated. Passage of virus down a leaf from the point of inoculation
is rapid, and can exceed 40 cm in 120 min (Storey, 1928
Crystalline nuclear inclusions occur in infected maize and sugarcane leaves
(Fig.6) (Bock et al., 1974; Sylvester, Richardson & Nickel, 1973);
they contain particles c. 18-20 nm in diameter.
and Martyn (1968)
cite maize mottle virus as a strain of maize
streak virus. However, there appears to be insufficient evidence to warrant
this assumption (Storey, 1937
). Recent work on the morphology of
beet curly top
, which is transmitted by the leafhopper Circulifer tenellus,
that its particles may be similar to the single particles of maize streak virus
(Duffus & Gold, 1973
In Africa, maize streak disease may be confused with diseases caused by maize line
or maize stripe viruses (Kulkarni, 1973). These viruses are transmitted by
Peregrinus maidis (and not by Cicadulina spp.); they also differ
in particle morphology, having spherical particles of 35 and 40 nm diameter
respectively. Maize mosaic virus (Herold, 1972) also induces leaf symptoms
that could be confused with those of maize streak but it has bacilliform
particles and is transmitted by Peregrinus maidis.
- Bock, Guthrie & Woods, Ann. appl. Biol. 77: 289, 1974.
- Cowan & Graves, Virology 34: 544, 1968.
- Duffus & Gold, Phytopathology 63: 1107, 1973.
- Herold, CMI/AAB Descriptions of Plant Viruses 94, 4 pp., 1972.
- Kulkarni, Ann. appl. Biol. 75: 205, 1973.
- Martyn, Phytopath. Pap. 9, 204 pp., 1968.
- McLean, Sci. Bull. Dep. Agric. For. Un. S. Afr. 265, 1947.
- Ruppel, Publs Mich. St. Univ. Mus. Biol. Ser 2: 385, 1965.
- Smith, Textbook of Plant Virus Diseases, London, Churchill, 1957.
- Storey, Ann. appl. Biol. 12: 422, 1925.
- Storey, Ann. appl. Biol. 15: 1, 1928.
- Storey, Proc. R. Soc. B. 112: 46, 1932.
- Storey, Proc. R. Soc. B. 113: 463, 1933.
- Storey, Ann. appl. Biol. 24: 87, 1937.
- Storey, Proc. R. Soc. B. 125: 455, 1938.
- Storey, Proc. R. Soc. B. 127: 526, 1939.
- Storey, Howland & Prosser, Rec. Res. E. Afr. Agric. For. Res. Org., 1965: 123, 1966.
- Storey & McLean, Ann. appl. Biol. 17: 691, 1930.
- Sylvester, Richardson & Nickel, Pl. Dis. Reptr 57: 414, 1973.
Streak disease symptoms in maize (type strain).
Streak disease symptoms in sugarcane cv. Co 678 (sugarcane strain).
Streak disease symptoms in guinea grass (Panicum maximum
Incipient systemic symptoms of maize (type) strain in maize seedling
10 days after inoculation.
Particles of type strain in uranyl acetate. Bar represents
Section of infected leaf of sugarcane showing 18-20 nm particles in
crystalline nuclear inclusion. Bar represents 0.5 µm