Plant Viruses Online   

Descriptions and Lists from the VIDE Database

Cucumber necrosis tombusvirus

Index

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

Data collated by D.M. Rochon, 1990.

Nomenclature

Acronym

CNV (CuNV)

ICTV decimal code

74.0.1.0.004

Host range and symptoms

Natural host range and symptoms

Symptoms vary seasonally. Symptoms malformed chlorotic or purplish leaves, which dessicate and die. Fruits mottled.
• Cucumis sativus - malformed chlorotic leaves.

Transmission

Transmitted by a vector and means not involving a vector (in water and soil); a fungus; Olpidium radicale; Chytridiales. Principal natural vector(s): Olpidium radicale. Not transmitted by Aphis gossypii. Virus transmitted by mechanical inoculation; transmitted by contact between plants; not transmitted by seed; not transmitted by pollen.

Ecology and control

Studies reported by Bos et al. (1984).

Geographical distribution

Spreads in Canada (Ontario).

Experimental host range

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

Diagnostically susceptible host species and symptoms

• Nicotiana clevelandii - necrotic local lesions, systemic necrosis.
• Nicotiana benthamiana - systemic necrosis.
• Chenopodium amaranticolor - small necrotic local lesions, no systemic infection.
• Vigna unguiculata - brown necrotic local lesions, no systemic infection.
• Gomphrena globosa - grey necrotic local lesions, no systemic infection.
• Nicotiana tabacum - grey necrotic spots, no systemic infection.

Maintenance and propagation hosts

Nicotiana clevelandii, Cucumis sativus.

Assay hosts (Local lesions or Whole plants)

Chenopodium amaranticolor (L), Vigna unguiculata (L), Gomphrena globosa (L).

Susceptible host species

• Chenopodium amaranticolor
• Chenopodium quinoa
• Cucumis sativus
• Gomphrena globosa
• Nicotiana benthamiana
• Nicotiana clevelandii
• Nicotiana tabacum
• Phaseolus vulgaris
• Vigna unguiculata

Families containing susceptible hosts

• Amaranthaceae (1/1)
• Chenopodiaceae (2/2)
• Cucurbitaceae (1/1)
• Leguminosae-Papilionoideae (2/2)
• Solanaceae (3/3)

Sources of host-range data

Dias and McKeen (1972).

Physical and biochemical properties

Properties of particles in sap

TIP: 75-80 °C (10 min). LIV: 30 days. DEP: log₁₀ minus 4-5. Leaf sap contains many virions.

Purification method

Tremaine et al. (1983).

Particle morphology

Virions isometric; not enveloped; 30 nm in diameter; angular in profile.

Physical properties

One sedimenting component in purified preparations; sedimentation coefficient 133 S. Density 1.33 g cm^-3 in CsCl. Isoelectric point pH 3.9 (pH).

Biochemical properties

Virions contain 16 % nucleic acid; 84 % protein; 0 % lipid.

Genome consists of RNA; single-stranded; linear. Total genome size 4.701 kb. Genome unipartite; largest (or only) genome part 4.7 kb. Genomic nucleic acid isolated by Rochon: phenol or chloroform extraction in buffer containing 10 mm EDTA, Tris-HCl pH 8.9, 1% SDS. Infectivity retained when deproteinised with phenol or detergent. Poly A region absent. Additional factor not required for infectivity. Genome has no tRNA-like activity.

NCBI sequence data (Entrez search)

Sequence database accession code(s)

• M25270 Gb(84)_vi:CNVGENO Cucumber necrosis virus, complete genome. 4/91 4,701bp.
• S64508 Em(40)_vi:S64508 Gb(84)_vi:S64508 (defective interfering RNA DI15) cucumber necrosis virus CNV, Genomic RNA, 622 nt. 12/93 62.
• U16698 Em(43)_vi:Cn16698 Gb(89)_vi:Cnu16698 Cucumber necrosis virus defective interfering RNA isolate C1. 11/94 432bp.
• U16699 Em(43)_vi:Cn16699 Gb(89)_vi:Cnu16699 Cucumber necrosis virus defective interfering RNA isolate C12. 11/94 432bp.
• U16700 Em(43)_vi:Cn16700 Gb(89)_vi:Cnu16700 Cucumber necrosis virus defective interfering RNA isolate C2. 11/94 432bp.
• U16701 Em(43)_vi:Cn16701 Gb(89)_vi:Cnu16701 Cucumber necrosis virus defective interfering RNA isolate C39. 11/94 594bp.
• U16702 Em(43)_vi:Cn16702 Gb(89)_vi:Cnu16702 Cucumber necrosis virus defective interfering RNA isolate C40. 11/94 411bp.
• U16703 Em(43)_vi:Cn16703 Gb(89)_vi:Cnu16703 Cucumber necrosis virus defective interfering RNA isolate C46. 11/94 416bp.
• U16704 Em(43)_vi:Cn16704 Gb(89)_vi:Cnu16704 Cucumber necrosis virus defective interfering RNA isolate C61. 11/94 594bp.
• U16705 Em(43)_vi:Cn16705 Gb(89)_vi:Cnu16705 Cucumber necrosis virus defective interfering RNA isolate C62. 11/94 597bp.
• U16706 Em(43)_vi:Cn16706 Gb(89)_vi:Cnu16706 Cucumber necrosis virus defective interfering RNA isolate C66. 11/94 414bp.

Features of the genome

Features of the genome: there are 5 ORFs; p33, p92, p41, p21 and p20. p33 and p92 are translated from the full length genomic RNA. p92 would be translated if suppression of the amber codon of p33 were to occur. p41, p21 and p20 are translated from subgenomic RNAs. p41 is coat protein, p92 is possibly a replicase protein, p33, p21 and p20 functions are unknown.

Non-genomic nucleic acid found in the virions; is subgenomic mRNA and of an unusual type of structure; defective interfering RNA. Sub-genomic mRNA found in infected cells; two subgenomic RNAs found in infected cells, 2.1 and 0.9 kb, and there are possibly others. 3 virus specified dsRNA species found in infected cells (also several minor ones). Size of largest virus specified dsRNA 4.7 kbp; 2nd largest 2.1 kbp; 3rd largest 0.9 kbp.

Features of proteins

Virion protein(s) one; M_r 41000; coat protein. Amino acid sequence: Rochon and Tremaine (1989). Amino acid composition: Rochon and Tremaine (1989). Virion proteins not glycosylated. Virion proteins not phosphorylated.

Replication

Replication does not depend on a helper virus.

Cytopathology

Virions found in mesophyll; in cytoplasm. Inclusions present in infected cells; are membranous bodies and unusual in shape; multivesicular bodies; they do not contain virions.

Taxonomy and relationships

Tombusvirus: Tombusviridae

Virus(es) with serologically unrelated virions

No serological relationship to several other tombusviruses.

Additional comments on relationships

Its possible replicase has similar amino acid sequence to the replicases of carnation mottle carmovirus, barley yellow dwarf luteovirus, tobacco necrosis necrovirus, red clover necrotic mosaic dianthovirus, maize chlorotic mottle machlomovirus and hepatitis C virus.

Comments and References

References

• Dias, H.F. and McKeen, C.D. (1972). CMI/AAB Descr. Pl. Viruses No. 82, 4 pp.
• Johnston, J.C. and Rochon, D.M. (1990). J. gen. Virol. 71: 2233.
• McKeen, C.D. (1959). Can. J. Bot. 37: 913.
• Riviere, C.J. and Rochon, D.M. (1990). J. gen. Virol. 71: 1887.
• Rochon, D.M. and Tremaine, J.H. (1988). Virology 69: 395.
• Rochon, D.M. and Tremaine, J.H. (1989). Virology 169: 251.
• Rochon, D.M., Johnston, J.C. and Riviere, C.J. (1991). Can. J. Pl. Pathol. 13: 162.

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.