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Descriptions and Lists from the VIDE Database

Squash mosaic comovirus

Index

• Nomenclature
• Host range, transmission and symptoms
• Physical and biochemical properties
• Taxonomy and relationships
• Comments and References

Data collated by R.N. Campbell, 1985.

Nomenclature

Synonyms

cucurbit ring mosaic virus, muskmelon mosaic virus, pumpkin mosaic virus (Stoner, 1963).

Acronym

SqMV

Strains

Arizona watermelon stunt virus; 2 serological groups, named I and II, have been recognized.

ICTV decimal code

18.0.1.0.015

Host range and symptoms

Natural host range and symptoms

• Cucumis melo, C. sativus, Cucurbita pepo, C. moschata, C. maxima - systemic mosaic, ringspots and leaf deformation.
• Ecballium elaterium - mild yellow mosaic (reported from Israel).
• Citrullus lanatus - infected by some isolates.
• Chenopodium album - one report from Morocco.

Transmission

Transmitted by a vector; an insect; Acalymma trivittata; A. thiemei thiemei; Diabrotica undecimpunctata undecimpunctata; D. bivittula; Epilachna chrysomelina; E. paenulata; Coleoptera. Transmitted in a non-persistent manner. Virus transmitted by mechanical inoculation; transmitted by seed (c. 10% in Cucumis melo and up to 35% in Cucurbita pepo); not transmitted by pollen (Alvarez and Campbell, 1978; Nolan and Campbell, 1984).

Geographical distribution

Probably distributed worldwide (presumably via imported seeds). Spreads in China. Found, but with no evidence of spread, in New Zealand.

Experimental host range

Few (<3) families susceptible.

Diagnostically susceptible host species and symptoms

• Cucumis melo, Cucurbita pepo - systemic mosaic, often with ringspots, leaf deformation.
• Cucumis metuliferus - chlorotic local lesions.

Diagnostically insusceptible host species

Chenopodium amaranticolor, Datura stramonium, Nicotiana glutinosa, N. tabacum cvs Turkish, Havana, Citrullus lanatus (resistant to all but the watermelon strain of SqMV).

Maintenance and propagation hosts

Cucurbita pepo, Cucumis melo.

Assay hosts (Local lesions or Whole plants)

Cucurbita pepo (W), Cucumis metuliferus - some collections e.g. P.I. 202681 or P.I. 292190 (L).

Susceptible host species

• Chenopodium album
• Chenopodium quinoa (in Morocco (Lockhart, 1982))
• Citrullus lanatus
• Cucumis melo
• Cucumis metuliferus
• Cucumis sativus
• Cucurbita maxima
• Cucurbita moschata
• Cucurbita pepo
• Ecballium elaterium
• Pisum sativum (in Morocco (Lockhart, 1982))

Insusceptible host species

• Abelmoschus esculentus
• Amaranthus retroflexus
• Antirrhinum majus
• Apium graveolens
• Arachis hypogaea
• Beta vulgaris (Lockhart (1982) found Beta vulgaris susceptible in Morocco)
• Brassica campestris ssp. rapa
• Brassica oleracea var. botrytis
• Brassica oleracea var. capitata
• Calendula officinalis
• Capsicum frutescens
• Catharanthus roseus
• Celosia argentea
• Cheiranthus cheiri
• Chenopodium amaranticolor
• Citrullus lanatus (when infected with Arizona strain)
• Datura stramonium
• Daucus carota
• Delphinium hybridum
• Dianthus caryophyllus
• Glycine max
• Gossypium hirsutum
• Helianthus annuus
• Ipomoea nil
• Lactuca sativa
• Lycopersicon esculentum
• Matthiola incana
• Medicago hispida
• Medicago sativa
• Melilotus albus
• Nicotiana glutinosa
• Nicotiana rustica
• Nicotiana tabacum
• Pastinaca sativa
• Petroselinum crispum
• Petunia × hybrida
• Phaseolus lunatus
• Phaseolus vulgaris
• Phlox drummondii
• Pisum sativum
• Raphanus sativus
• Ricinus communis
• Rumex acetosa
• Solanum tuberosum
• Spinacia oleracea
• Trifolium incarnatum
• Trifolium pratense
• Trifolium repens
• Tropaeolum majus
• Vicia faba
• Vigna unguiculata
• Vigna unguiculata ssp. sesquipedalis
• Zea mays
• Zinnia elegans

Families containing susceptible hosts

• Chenopodiaceae (2/5)
• Cucurbitaceae (8/8)
• Leguminosae-Papilionoideae (1/14)

Families containing insusceptible hosts

• Amaranthaceae (2/2)
• Apocynaceae (1/1)
• Caryophyllaceae (1/1)
• Chenopodiaceae (3/5)
• Compositae (4/4)
• Convolvulaceae (1/1)
• Cruciferae (6/6)
• Cucurbitaceae (1/8)
• Euphorbiaceae (1/1)
• Gramineae (1 /1)
• Leguminosae-Papilionoideae (14/14)
• Malvaceae (2/2)
• Polemoniaceae (1/1)
• Polygonaceae (1/1)
• Ranunculaceae (1/1)
• Scrophulariaceae (1/1)
• Solanaceae (8/8)
• Tropaeolaceae (1/1)
• Umbelliferae (4 /4)

Sources of host-range data

Freitag (1956); Lockhart (1982).

Physical and biochemical properties

Properties of particles in sap

TIP: 70-80 °C. LIV: 30 days. DEP: log₁₀ minus 4-6.

Purification method

Alvarez and Campbell (1978).

Particle morphology

Virions isometric; not enveloped; 28 nm in diameter; angular in profile; without a conspicuous capsomere arrangement.

Physical properties

Three sedimenting components in purified preparations; sedimentation coefficient of the fastest 118 S (B); of the other(s) 95 S (M), or 57 S (T). Isoelectric point pH 4.56 (Rice et al., 1955).

Biochemical properties

Virions contain 35 % nucleic acid (B), or 27 % nucleic acid (M), or 0 % nucleic acid (T); 65 % protein (B), or 73 % protein (M), or 100 % protein (T).

Genome consists of RNA; single-stranded; linear. Total genome size 11.2 kb. Genome of two parts; largest (or only) genome part the larger 6.8 kb; the 2nd largest 4.5 kb (Mazzone et al., 1962). Genomic nucleic acid isolated by Hiebert and Purcifull (1981). Base composition 22.5 % G; 31.6 % A; 16.2 % C; 29.5 % U. 5´ terminus of RNA has a VPg. Poly A region present; Daubert and Bruening, 1979 at the 3' end.

NCBI sequence data (Entrez search)

Sequence database accession code(s)

• M96148 Em(40)_vi:COMSQVCAP Gb(84)_vi:SQVCAPPRO Squash Moasic Virus 42 kDa capsid protein and 22 kDa capsid protein. 7/93 2,536bp. 1 sequence.

Features of the genome

Non-genomic nucleic acid not found in the virions.

Features of proteins

Virion protein(s) three; M_r of the largest 42000; coat protein. M_r of 2nd largest 22000; coat protein. M_r of 3rd largest 5000; genome-linked protein (VPg) - data given are based on analogy to other comoviruses, see Daubert and Bruening 1979 and 1984. Method of preparation: Hiebert and Purcifull (1981). Amino acid composition: Mazzone et al. (1962).

Virus-coded non-virion proteins isolated (Hiebert and Purcifull (1981)); six proteins found. M_r of the largest 190000. M_r of 2nd largest 51000. M_r of 3rd 32000 (all translations of B-RNA). M_r of 4th 112000. M_r of 5th and smaller 105000, or 90000, or 64000, or 40000, or 22000 (all translations of M-RNA, except the last value).

Replication

Replication does not depend on a helper virus.

Cytopathology

Virions found in all parts of the host plant.

Taxonomy and relationships

Comovirus: Comoviridae

Virus(es) with serologically related virions

Cowpea severe mosaic (Arkansas strain), radish mosaic, bean pod mottle, glycine mosaic, quail pea mosaic and broad bean stain viruses.

Virus(es) with serologically unrelated virions

Andean potato mottle virus.

Comments and References

References

• Alvarez, M. and Campbell, R.N. (1978). Phytopathology 68: 257.
• Bruening, G. (1978). CMI/AAB Descr. Pl. Viruses No. 199, 5 pp.
• Campbell, R.N. (1971). CMI/AAB Descr. Pl. Viruses No. 43, 4 pp.
• Daubert, S.D. and Bruening, G. (1979). Virology 98: 246.
• Daubert, S.D. and Bruening, G. (1984). In: Methods in Virology, Vol. 8, pp. 364-365; eds. K. Maramorosch and H. Koprowski. Academic Press, New York.
• Freitag, J.H. (1956). Phytopathology 46: 73.
• Hiebert, E. and Purcifull, D.E. (1981). Virology 113: 630.
• Lindberg, G.D., Hall, D.H. and Walker, J.C. (1956). Phytopathology 46: 489.
• Lockhart, B.E.L. (1982). Plant Dis. 66: 1191.
• Mazzone, H.M., Incardona, N.L. and Kaesberg, P. (1962). Biochim. biophys. Acta 55: 164.
• Nolan, P.A. and Campbell, R.N. (1984). Plant Dis. 68: 971.
• Rice, R.V., Lindberg, G.D., Kaesberg, P., Walker, J.C. and Stahmann, S.H. (1955). Phytopathology 45: 145.
• Stoner, W.N. (1963). Phytopathology 53: 890.

Cite this publication as: Brunt, A.A., Crabtree, K., Dallwitz, M.J., Gibbs, A.J., Watson, L. and Zurcher, E.J. (eds.) (1996 onwards). `Plant Viruses Online: Descriptions and Lists from the VIDE Database. Version: 20^th August 1996.' URL http://biology.anu.edu.au/Groups/MES/vide/

Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993) should also be cited.