Plant Viruses Online   

Descriptions and Lists from the VIDE Database

Cacao necrosis nepovirus

Index

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

Data collated by A.A. Brunt, 1984.

Nomenclature

Synonyms

cacao swollen shoot virus - strain S.

Acronym

CNV

ICTV decimal code

18.0.3.0.011

Host range and symptoms

Natural host range and symptoms

• Theobroma cacao - systemic, necrotic or chlorotic spots, streaks and mosaic.

Transmission

Transmitted by a vector; a nematode (possibly). Virus transmitted by mechanical inoculation; transmitted by grafting; not transmitted by contact between plants; transmitted by seed (up to 24% in Glycine max, Phaseolus lunatus and P. vulgaris).

Geographical distribution

Spreads in Ghana and Nigeria.

Experimental host range

Several (3-9) families susceptible. Experimentally infected plants mostly show necrotic local lesions, systemic mottling.

Diagnostically susceptible host species and symptoms

• Beta vulgaris - red local lesions.
• Chenopodium amaranticolor, C. quinoa - systemic leaf chlorosis.
• Phaseolus vulgaris - chlorotic local lesions or ringspots; systemic vein-banding and mottling.

Diagnostically insusceptible host species

Spinacia oleracea, Trifolium repens, Vicia faba, Datura stramonium.

Maintenance and propagation hosts

Phaseolus vulgaris.

Assay hosts (Local lesions or Whole plants)

Beta vulgaris (L), but less sensitive than Phaseolus vulgaris (L).

Susceptible host species

• Beta vulgaris
• Chenopodium amaranticolor
• Chenopodium quinoa
• Cucumis sativus
• Glycine max
• Gomphrena globosa
• Nicotiana clevelandii
• Nicotiana glutinosa
• Nicotiana tabacum
• Petunia × hybrida
• Phaseolus vulgaris
• Tetragonia tetragonioides
• Theobroma cacao
• Vigna unguiculata

Insusceptible host species

• Brassica campestris ssp. pekinensis
• Brassica campestris ssp. rapa
• Capsicum annuum
• Datura stramonium
• Daucus carota
• Hyoscyamus niger
• Lactuca sativa
• Lycopersicon esculentum
• Pastinaca sativa
• Physalis floridana
• Pisum sativum
• Raphanus sativus
• Spinacia oleracea
• Trifolium repens
• Triticum aestivum
• Vicia faba

Families containing susceptible hosts

• Amaranthaceae (1/1)
• Chenopodiaceae (3/4)
• Cucurbitaceae (1/1)
• Leguminosae-Papilionoideae (3/6)
• Solanaceae (4/9)
• Sterculiaceae (1/1)
• Tetragoniaceae (1/1)

Families containing insusceptible hosts

• Chenopodiaceae (1/4)
• Compositae (1/1)
• Cruciferae (3/3)
• Gramineae (1/1)
• Leguminosae-Papilionoideae (3/6)
• Solanaceae (5/9)
• Umbelliferae (2/2)

Sources of host-range data

Kenten (1972).

Physical and biochemical properties

Properties of particles in sap

TIP: 65 °C. LIV: 4-7 days. DEP: log₁₀ minus 3-4. Leaf sap contains few virions.

Purification method

Kenten (1972).

Particle morphology

Virions isometric; not enveloped; 24-26 nm in diameter (a minor component of 20-30 S has isometric virions 12 nm diameter); angular in profile; without a conspicuous capsomere arrangement.

Physical properties

Four sedimenting components in purified preparations (one of which may be polymerized coat protein); sedimentation coefficient of the fastest 129 S (B); of the other(s) 101 S (M), or 54 S (T). A₂₆₀/A₂₈₀ ratio 1.78 (B), or 1.63 (M; both corrected for scattering).

Biochemical properties

Virions contain 38 % nucleic acid (B), or 26 % nucleic acid (M), or 0 % nucleic acid (T); 62 % protein (B), or 74 % protein (M), or 100 % protein (T); 0 % lipid.

Genome consists of RNA; single-stranded; linear; of two parts.

Features of proteins

Virion protein(s) one; M_r 60000.

Taxonomy and relationships

Nepovirus: Comoviridae

Virus(es) with serologically related virions

Tomato black ring virus, but distantly, and grapevine chrome mosaic virus, very distantly.

Virus(es) with serologically unrelated virions

Arabis mosaic, cherry leaf roll, strawberry latent ringspot, tobacco ringspot and tomato ringspot viruses.

Comments and References

References

• Kenten, R.H. (1972). Ann. appl. Biol. 71: 119.
• Kenten, R.H. (1977). CMI/AAB Descr. Pl. Viruses No. 173, 4 pp.
• Owusu, G.K. (1971). Trop. Agric., Trin. 48: 133.
• Thresh, J.M. and Tinsley, T.W. (1959). Tech. Bull. W. Afr. Cocoa Res. Inst. No. 7, p. 27.

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.