174
September 1977
Family: Rhabdoviridae
Genus: Unassigned Rhabdoviridae
Species: Raspberry vein chlorosis virus
Acronym: RVCV


Raspberry vein chlorosis virus

A. T. Jones
Scottish Horticultural Research Institute, Invergowrie, Dundee, Scotland

A. F. Murant
Scottish Horticultural Research Institute, Invergowrie, Dundee, Scotland

R. Stace-Smith
Agriculture Canada Research Station, Vancouver B.C., Canada

Contents

Introduction
Main Diseases
Geographical Distribution
Host Range and Symptomatology
Strains
Transmission by Vectors
Transmission through Seed
Transmission by Grafting
Transmission by Dodder
Serology
Nucleic Acid Hybridization
Relationships
Stability in Sap
Purification
Properties of Particles
Particle Structure
Particle Composition
Properties of Infective Nucleic Acid
Molecular Structure
Genome Properties
Satellites
Relations with Cells and Tissues
Ecology and Control
Notes
References
Acknowledgements
Figures

Introduction

Described by Cadman (1952).

Synonym

Raspberry chlorotic net virus (Rev. appl. Mycol. 43: 799)

A bacilliform virus with enveloped particles, measuring c. 430-500 x 65-80 nm in sections of raspberry. Transmitted by aphids but not by mechanical inoculation of sap. Important in Rubus in Europe; reported also in Canada and New Zealand.

Main Diseases

Natural infections occur in cultivated and wild red raspberry (Rubus idaeus). In most cultivars the virus induces a chlorosis of the minor leaf veins to form a yellow net pattern which in some cultivars is uniform throughout the young leaves (Fig.1) but in others is patchy (Fig.2). Some cultivars also show leaf deformity and epinasty (Jordovic, 1963); a few show no obvious symptoms of infection. Stocks of some cultivars such as Baumforth’s B are totally infected.

Geographical Distribution

Common in Europe (Cadman, 1952; Jordovic, 1963; Richter, 1964; Bjørnstad, 1958; Tapio, 1961) and USSR (Kuznetsova & Pomazkov, 1971). It has also been introduced into Canada (Stace-Smith, 1961) and New Zealand (Cadman & Stace-Smith, 1970) in infected R. idaeus cv. Lloyd George.

Host Range and Symptomatology

The virus has few hosts apart from R. idaeus. It has however been transmitted by grafting to loganberry (R. loganobaccus) and by aphids to Fragaria vesca (Stace-Smith, 1961).

Diagnostic species

R. idaeus cvs. Lloyd George, Malling Delight, Norfolk Giant and Washington. About 4-8 weeks after inoculation by grafting or by aphids, chlorosis of the minor veins develops in small patches in young expanding leaves (Fig.1, Fig.2). The leaf blade remains normal but may become distorted by uneven growth as the leaf expands. As the leaf ages the symptoms become less distinct and may disappear. Symptoms are less intense in the glasshouse than in the field and depend also on the virus isolate used (see Strains). In cv. Malling Delight, these symptoms are frequently accompanied by epinasty and stunting of young expanding leaves. Interpretation of the reactions of indicator cultivars may be difficult when other viruses are present.

R. idaeus (cvs. Cuthbert, Latham and Viking), R. occidentalis and R. henryi are immune (Cadman, 1952; Stace-Smith, 1961).

Fragaria vesca (Alpine strawberry). Symptoms are similar to those in R. idaeus cv. Lloyd George but in addition veinal chlorosis often develops along one of the secondary leaf veins.

Propagation and assay species

The susceptible R. idaeus cultivars listed above are suitable for maintaining cultures and some have also been used for assaying transmission by aphids.

Strains

Cadman (1952) distinguished mild, moderate and severe forms of vein chlorosis in red raspberry, possibly caused by three different strains of the same virus.

Transmission by Vectors

Transmitted by Aphis idaei but not by the other main aphid vectors of Rubus viruses, Amphorophora rubi and A. agathonica (Cadman & Hill, 1947; Cadman, 1952; Stace-Smith, 1961; Jordovic, 1963). Information on virus-vector relations is scanty but aphids required at least 1 day to acquire the virus and retained it for at least 1 day (Cadman, 1952; Stace-Smith, 1961). Efficiency of transmission is increased after 7-day acquisition access feeds (Cadman, 1952), the greatest recorded frequencies of transmission (46%) being obtained after acquisition and inoculation access periods of 7 days and 30 days respectively (Jordovic, 1963).

Transmission through Seed

Not found in red raspberry (Jordovic, 1963).

Transmission by Dodder

None reported.

Serology

No information available.

Relationships

Particle morphology places raspberry vein chlorosis virus in the rhabdovirus group. It resembles lettuce necrotic yellows (Francki & Randles, 1970), sowthistle yellow vein (Peters, 1971), broccoli necrotic yellows (Campbell & Lin, 1972) and strawberry crinkle (Sylvester, Frazier & Richardson, 1976) viruses in being aphid-transmitted.

Stability in Sap

Unlike most other aphid-borne viruses occurring in Rubus, it is not inactivated in infected raspberry plants by exposure to 37°C for several weeks or months (Stace-Smith, 1960; Chambers, 1961; Jordovic, 1963). However, some virus-free plants were obtained by rooting excised tips from infected plants that had been kept at 35°C for 4 weeks (van der Meer, 1975).

Purification

No information.

Properties of Particles

No information.

Particle Structure

In thin sections of infected raspberry tissue bacilliform particles of two kinds (Fig.3) are observed: (a) particles rounded at both ends and measured as c. 442-560 x 73-91 nm by Stace-Smith & Lo (1973), and as c. 430-500 x 65-80 nm by Jones, Roberts & Murant (1974); and (b) shorter particles rounded at one end. The particles have a densely staining nucleocapsid c. 25-30 nm in diameter surrounded by an electron lucent zone and then by a unit membrane (Fig.5) which in some sections appears to be continuous with the endoplasmic reticulum. The nucleocapsid shows some cross-banding with a periodicity of c. 4-5 nm (Fig.4) (Stace-Smith & Lo, 1973; Jones et al, 1974).

Particle Composition

No information.

Relations with Cells and Tissues

Particles appear to be confined to a small proportion of parenchyma cells of the vascular bundles. Many cells of this region have wall projections into the cytoplasm, hypertrophied mitochondria and enlarged perinuclear spaces. Particles occur singly or in groups in the cytoplasm and perinuclear space (Fig.6) but not in the nucleus and are often found in groups enclosed within a membraneous sac (Fig.5) (Stace-Smith & Lo, 1973; Jones et al., 1974).

Notes

Virus-like particles and ultrastructural effects resembling those of raspberry vein chlorosis virus were first found by Putz & Meignoz (1972) in raspberry showing veinbanding mosaic. However, it is now known that of the two viruses responsible for this disease, black raspberry necrosis virus has spherical particles c. 25 nm in diameter (Jones & Murant, 1972; Murant, Jones & Roberts, 1976) and rubus yellow net virus has small bacilliform particles c. 80-150 x 25-31 nm (Jones & Roberts, 1976; Stace-Smith & Leung, 1976). Therefore the plants examined by Putz & Meignoz were probably also infected with raspberry vein chlorosis virus.

Symptoms induced by rubus yellow net virus in some red raspberry cultivars can be similar to those induced by raspberry vein chlorosis virus (Stace-Smith, 1955). However the viruses are transmitted by different aphid species (Cadman & Hill, 1947) and have different sizes of particles (Jones & Roberts, 1976). They can be distinguished in pure culture by graft indexing to black raspberry (R. occidentalis), which is immune to raspberry vein chlorosis virus but develops a yellow net symptom on infection with rubus yellow net virus (Stace-Smith, 1955).

References

  1. Bjørnstad, Norsk Hagetid. 74: 80, 1958.
  2. Cadman, Ann. appl. Biol. 39: 61, 1952.
  3. Cadman & Hill, Nature, Lond. 160: 837, 1947.
  4. Cadman & Stace-Smith, In Virus Diseases of Small Fruits and Grapevines, p. 119, University of California Press, 1970.
  5. Campbell & Lin, CMI/AAB Descriptions of Plant Viruses 85, 4 pp., 1970.
  6. Chambers, J. hort. Sci. 36: 48, 1961.
  7. Francki & Randles, CMI/AAB Descriptions of Plant Viruses 26, 4 pp., 1970.
  8. Jones & Murant, Pl. Path. 21: 166, 1972.
  9. Jones & Roberts, Ann. appl. Biol. 84: 305, 1976.
  10. Jones, Roberts & Murant, Ann. appl. Biol. 77: 283, 1974.
  11. Jordovic, Arh. poljopr. Nauke Teh. 16: 3, 1963.
  12. Kuznetsova & Pomazkov, Biol. Nauki 14: 92, 1971.
  13. Murant, Jones & Roberts, Acta Hort. 66: 39, 1976.
  14. Peters, CMI/AAB Descriptions of Plant Viruses 62, 3 pp., 1971.
  15. Putz & Meignoz, Phytopathology 62: 1477, 1972.
  16. Richter, Arch. Gartenb. 12: 517, 1964.
  17. Stace-Smith, Can. J. Bot. 33: 314, 1955.
  18. Stace-Smith, Can. Pl. Dis. Surv. 40: 24, 1960.
  19. Stace-Smith, Can. J. Bot. 39: 559, 1961.
  20. Stace-Smith & Lo, Can. J. Bot. 51: 1343, 1973.
  21. Stace-Smith & Leung, Proc. Am. Phytopath. Soc. 3: 320, 1976.
  22. Sylvester, Frazier & Richardson, CMI/AAB Descriptions of Plant Viruses 163, 4 pp., 1976.
  23. Tapio, Valt. Maatalouskoet. Julk. 184, 21 pp., 1961.
  24. van der Meer, Bull. Recherches agron. Gembloux Special Volume: 109, 1975.

Acknowledgements

Figs. 2, 5 courtesy Agriculture Canada Research Station, Vancouver; other figures courtesy Scottish Horticultural Research Institute, Dundee.


Figure 1

Leaf symptoms in raspberry (R. idaeus) infected with raspberry vein chlorosis virus. SHRI selection 6820/54, naturally infected.

Figure 2

Leaf symptoms in raspberry (R. idaeus) infected with raspberry vein chlorosis virus. cv. Lloyd George, naturally infected.

Figure 3

Particles of raspberry vein chlorosis virus in thin sections of infected raspberry leaf cells. Particles rounded at one or both ends. Bar represents 100 nm.

Figure 4

Particles of raspberry vein chlorosis virus in thin sections of infected raspberry leaf cells. Particle showing cross-banding of the nucleocapsid. Bar represents 100 nm.

Figure 5

Particles of raspberry vein chlorosis virus in thin sections of infected raspberry leaf cells. Membraneous sac containing a group of particles seen in cross-section. Bar represents 100 nm.

Figure 6

Particles of raspberry vein chlorosis virus in thin sections of infected raspberry leaf cells. Particles in enlarged perinuclear space. N = nucleus. Bar represents 500 nm.