Potato virus S
Botanisches Institut, Universität des Saarlandes, 66 Saarbrücken, Germany
- Described by De Bruyn Ouboter (1952) and Rozendaal (1952).
- A virus with straight to slightly curved filamentous particles c.
650 x 12 nm. It is sap-transmissible to a limited range of species. Some isolates
aphid-transmissible. World-wide distribution.
Causes few or no symptoms and is carried by many cultivated potato varieties.
Decreases yield of potato tubers by up to 20%.
World-wide in cultivated varieties of potato.
Host Range and Symptomatology
Host range is narrow. Susceptible species belong mainly to the families
Solanaceae and Chenopodiaceae. Transmissible by inoculation with sap from young
fully expanded potato leaves but not from older leaves. Infected potato leaves
may show slight chlorosis, roughness of the surface and undulation of the margin
- Diagnostic species
- Chenopodium amaranticolor, C. quinoa, C. album. Chlorotic local lesions
1-2 mm in diameter about 20 days after inoculation; lesions on old yellow leaves
are surrounded by a green halo. Not systemic (Fig.3).
- Solanum rostratum. Numerous small necrotic local lesions about 20 days
after inoculation. Systemically infected leaves show similar symptoms (Fig.4).
- Nicotiana debneyi. No symptoms in the inoculated leaves. Systemically
infected leaves show vein-clearing and mottling, becoming necrotic (Fig.2).
- Cyamopsis tetragonoloba (guar). Small brown necrotic local lesions on
cotyledons after about 10 days. Not systemic.
- Propagation species
- Potato varieties. Nicotiana clevelandii (M. Hollings, pers. comm.).
- Assay species
- Chenopodium amaranticolor, C. quinoa, C. album.
There are no well defined strains, only minor variants. De Bokx (1968)
differentiated isolates by their rate of translocation within the potato plant.
Transmission by Vectors
Isolates may differ in their transmissibility by Myzus persicae
isolate from US seedling 41956 could not be transmitted under conditions in which
the related potato virus M
was transmitted (Wetter & Völk, 1960
other isolates were transmitted by Myzus persicae
(Bode & Weideman, 1970
Transmission through Seed
Seeds produced by systemically infected Solanum demissum
healthy seedlings (Wetter, unpubl.).
Transmission by Dodder
Antisera with titres up to 1/65,000 were obtained by primary intravenous
injections of partially purified virus preparations followed by intramuscular
injections with antigen mixed with Freunds complete or incomplete adjuvant
). The precipitate in precipitin tube tests is flagellar. Several
kinds of test have been used in diagnosis of infection in potato: the
microprecipitin (Van Slogteren, 1955
), bentonite flocculation (Kahn et al.,
), and latex (Bercks, 1967
) tests. For comparative studies with related
viruses double diffusion tests in gels have been employed (Wetter, 1967
Serological tests are the best way of diagnosing the virus.
Potato virus S is distantly serologically related to the following viruses
which together form the potato virus S group
(Brandes & Wetter, 1959
), potato M
(Bagnall, Larson & Walker,
; Bagnall, Wetter & Larson, 1959
), chrysanthemum B
Slogteren & De Vos, 1962
), passiflora latent (Brandes & Wetter, 1963
cactus 2 (Brandes & Wetter, 1963) and red clover vein mosaic
Other viruses which have similar particles and are possibly related include
freesia mosaic, hop mosaic
and poplar mosaic
Stability in Sap
Thermal inactivation point is 55-60°C, dilution end-point is
and infectivity is retained at 20°C for
. Extract sap from infected potato leaves and add ascorbic
acid to 0.2% (w/v) and sodium sulphite to 0.2% (w/v). Filter, and shake
filtrate with an equal volume of ether. Centrifuge, and shake clarified
aqueous phase with an equal volume of carbon tetrachloride. Sediment and
clarify by two cycles of high and low speed centrifugation, resuspending the
pellets in 0.01 M phosphate buffer. Density gradient centrifugation can be
used to free the partially purified virus from host material.
Properties of Particles
Particles are straight, sometimes curved, filaments with modal length of
650 x 12 nm (Fig.5
) (Wetter & Brandes, 1956
; De Bokx, 1969
Relations with Cells and Tissues
Potato virus S is found in some potato varieties together with strains of
the aphid- transmissible and serologically related potato virus M
. Potato virus
S may be obtained from the mixture by inoculating Nicotiana debneyi
which is systemically invaded by potato virus S, whereas potato virus M
remains localized in the inoculated leaves.
- Bagnall, Larson & Walker, Res. Bull. agric. Exp. Stn Univ. Wis. 198, 45 pp., 1956.
- Bagnall, Wetter & Larson, Phytopathology 49: 435, 1959.
- Bercks, Phytopath. Z. 58: 1, 1967.
- Bode & Weideman, Proc. 4th trienn. Conf. Eur. Ass. Potato Res., Brest, 1969: 224, 1970.
- Brandes, Mitt. biol. BundAnst. Ld- u. Forstw. 110, 130 pp., 1964.
- Brandes & Wetter, Virology 8: 99, 1959.
- Brandes & Wetter, Phytopath. Z. 49: 61, 1963.
- De Bokx, Meded. Rijksfac. LandbWetensch. Gent 33: 1179, 1968.
- De Bokx, Neth. J. Pl. Path. 75: 144, 1969.
- De Bruyn Ouboter, Proc. 1st Conf. Potato Virus Diseases, Lisse- Wageningen, 1951: 83, 1952.
- Hakkaart, Van Slogteren & De Vos, Tijdschr. PlZiekt. 63: 126, 1962.
- Kahn, Scott, Bozicevich & Vincent, Phytopathology 57: 61, 1967.
- Kassanis, Ann. appl. Biol. 43: 103, 1955.
- Kassanis, J. gen. Microbiol. 15: 620, 1956.
- Rozendaal, Meded. ned. alg. KeurDienst LandbZaken Aardappelpootg. 8: 94, 1952.
- Van Slogteren, Proc. 2nd Conf. Potato Virus Diseases, Lisse-Wageningen, 1954: 51, 1955.
- Wetter, Arch. Mikrobiol. 37: 278, 1960.
- Wetter, Z. Naturf. B 22: 1008, 1967.
- Wetter & Brandes, Phytopath. Z. 26: 81, 1956.
- Wetter & Völk, Eur. Potato J. 3: 158, 1960.
The support of the Deutsche Forschungsgemeinschaft is gratefully
Photographs: Figs 3 and 4 courtesy of Dr M. Vulic; Fig.5 courtesy
of the late Dr J. Brandes.
Solanum demissum x S. tuberosum cv. Aquila (=A6 hybrid).
(Right) healthy plant, (left) systematically infected plant with
rough leaf surface and undulation of leaf margins.
Systematically infected leaves of Nicotiana debneyi.
Inoculated leaf of Chenopodium amaranticolor, showing local
Systematically infected leaf of Solanum rostratum, showing
Virus particles from a leaf dip preparation. Bar represents 400 nm.