373
April 2000
Family: Geminiviridae
Genus: Begomovirus
Species: Abutilon mosaic virus
Acronym: AbMV


Abutilon mosaic virus

H. Jeske
Universität Stuttgart, Biologisches Institut, Lehrstuhl für Molekularbiologie und Virologie der Pflanzen, Pfaffenwaldring 57, D-70550 Stuttgart, Germany.

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

Disease first described by Baur (1906). Virus first purified by Abouzid & Jeske (1986).

Selected synonyms:

Infectious chlorosis of Malvaceae (Hertzsch, 1928)
Abutilon infectious variegation (Brierley, 1944)
Marmor abutilon (Holmes, 1948)
Abutilon virus 1 (Smith, 1957)

A geminivirus containing single-stranded DNA. The host range includes species in the Malvaceae, Leguminosae, Solanaceae and Euphorbiaceae. Transmitted mainly by grafting and rarely by the whitefly, Bemisia tabaci. The virus is restricted to the phloem and is transmissible mechanically to only a few test species. Of historical interest, being one of the first viruses described.

Main Diseases

Causes mosaic (variegation) in leaves of malvaceous plants notably Abutilon species (Fig.1), in which the mosaic is regarded as decorative, and is of economic value. No detrimental effects on crop plants known. On weeds (Malva spp.; Nicotiana benthamiana) the virus causes mosaic, stunting or necrosis.

Geographical Distribution

Originates from the West Indies or Brazil. Distributed world-wide in ornamental Abutilon spp.

Host Range and Symptomatology

Host range includes species of Malvaceae, Euphorbiaceae, Leguminosae, Solanaceae, Sterculiaceae, Tiliaceae and Urticaceae (Silberschmidt, 1943; 1945; 1948; Costa & Bennett, 1950; Silberschmidt & Tommasi, 1953; 1956; Crandall, 1954; Costa, 1955; Silberschmidt et al., 1957; Bird, 1958; Costa & Carvalho, 1960b). The virus has been transmitted by whiteflies (Orlando & Silberschmidt, 1946), by grafting and, occasionally, by sap inoculation (Costa & Carvalho, 1960a).

Diagnostic species

Malva parviflora (Fig.2). Yellow mosaic and stunting. The first systemically infected leaves show vein-clearing and downward curling.

Propagation and assay species

Not mechanically transmissible from Abutilon spp. A good source of inoculum is Sida micrantha grafted onto infected Abutilon. Mechanically inoculated Malva parviflora plants, kept at 30 °C and 16 h day length (10 000 lux), are a moderate source of virus for purification. Harvesting half expanded, systemically infected leaves at 8 a.m. is optimal for purification (Abouzid & Jeske, 1986; Jeske, 1986). Yields vary from 1 to 10 mg virus per kg tissue. No local lesion host-plant is known. Best propagation is by agroinfection of cloned AbMVa-DNA (Frischmuth et al., 1990; Evans & Jeske, 1993a; 1993b) onto Nicotiana benthamiana or Malva parviflora. Back transmission of AbMV from agroinfected M. parviflora to Abutilon spp. is possible by grafting (Wege et al., 2000), fullfilling completely Koch's postulates for the West Indian isolate.

Strains

No bona fide strains have been distinguished on biological grounds but isolates have been from two geographic sources. Classically described (Hertzsch, 1928; Flores & Silberschmidt, 1967) "strain A" was from Abutilon striatum (syn. A. pictum) "Thompsonii", originally from the West Indies, and "strain B" was from Abutilon striatum var. spurium, naturally occurring in Brazil. Two different sources of AbMV have been used in the course of the cited studies: one (for "AbMV") was an ornamental Abutilon sellovianum plant, originating from the West Indies (Regel, 1868), and the other (for "AbMVb") was Sida micrantha (Fig.3), naturally infected in Brazil (Costa & Carvalho, 1960a). The plant called "Abutilon sellovianum var. marmorata" was produced by grafting Abutilon striatum var. Thompsonii (infected with the West Indian isolate) onto uninfected Abutilon sellovianum (which was collected from Brazil) (Regel, 1868). The biological properties of the two isolates described are similar, thus giving rise to the classical nomenclature of AbMV (Costa & Carvalho, 1960a; Flores & Silberschmidt, 1961/62; 1967). However, the nucleotide sequence of AbMVb (Zimmat & Jeske, unpublished) shows such a divergence from that of AbMVa (Frischmuth et al., 1990) that AbMVb should be considered a separate begomovirus. It is as closely related to tomato golden mosaic virus and bean golden mosaic virus as it is to AbMVa.

Transmission by Vectors

The Brazilian isolate of AbMV was transmitted by the whitefly Bemisia tabaci (Orlando & Silberschmidt, 1945; 1946; Silberschmidt & Tommasi, 1953; 1956; Costa, 1955; Silberschmidt et al., 1957; Costa & Carvalho, 1960b; Flores & Silberschmidt, 1961/62; 1963; 1966; 1967). A single whitefly is sufficient for transmission, females being more effective than males. Minimum total acquisition and inoculation time is 15-20 min. Attempts to transmit the West Indian isolate by whiteflies from vegetatively propagated ornamental Abutilon have so far been unsuccessful, suggesting that the virus in these plants may have lost some factor required for whitefly transmission. Replacement of the AbMVa coat protein gene by the homologous gene of Sida Golden Mosaic Virus from Costa Rica rendered AbMVa whitefly transmissible (Höfer et al., 1997a).

Transmission through Seed

Not seed-transmitted. Earlier claims of Keur (1934) have not been substantiated (Costa, 1955; unpublished observations).

Serology

Antiserum has been prepared in mice (Abouzid et al., 1988a). The reaction end-point in ELISA was 10-5. Some monoclonal antibodies against African cassava mosaic begomovirus cross-react with AbMV (Macintosh et al., 1992).

Relationships

Judging by nucleotide sequence comparisons (Howarth & Vandemark, 1989), AbMVa is related to tomato golden mosaic and bean golden mosaic begomoviruses. However, the nearest relative on this basis is tomato mottle begomovirus from Florida (Abouzid et al., 1992). Pseudo-recombination has been obtained between AbMVa and SiGMV-Co (Höfer et al., 1997b), and between AbMVa and SiGMV-Hoyv (Unseld et al., 2000).

Stability in Sap

In sap of Sida spp. the thermal inactivation point (10 min) is 55 °C, the dilution end-point is 10-2 and the longevity in vitro is 48 h (Costa & Carvalho, 1960a).

Purification

From infected Malva parviflora at 4 °C: Homogenize in 0.1 M Na-phosphate, pH 7.0, 10 mM Na2SO3, 10 mM NaN3, 2 mM EDTA and 1% polyvinylpyrrolidone (10 to 20 ml per g tissue). Filter through muslin and clear by low speed centrifugation. Extract the supernatant fluid with 0.5 vol. chloroform for 1 h. Collect the aqueous phase and precipitate the virus by addition of 1/9 vol. of a solution of 40% polyethylene glycol 6000 and 2 M NaCl and stirring for 2 h. Resuspend the pellet in 0.1 M Na-phosphate, pH 7.0 and purify by differential centrifugation (10 min, 12000 g; 60 min, 178000 g) and isopycnic centrifugation in Cs2SO4 (Abouzid & Jeske, 1986).

Properties of Particles

Sedimentation coefficient (s20,w): 82 S; buoyant density in Cs2SO4: 1.30 g/cm3; A260/280: 1.55 to 1.57 (Abouzid & Jeske, 1986).

Particle Structure

The particles are geminate, about 17 nm x 29 nm (Fig.4). The particles structure is resolved best in uranyl acetate (Abouzid et al., 1988b), less well in phosphotungstate, pH 3 (Abouzid & Jeske, 1986).

Particle Composition

Nucleic acid: Circular single-stranded DNA of mol. wt. 0.87 x 106 (18 % of the particle weight). The genome is bipartite, comprising DNA-A with 2629 bases and DNA-B with 2585 bases (Frischmuth et al., 1990).

Proteins: Two bands in sodium dodecyl sulphate polyacrylamide gel electrophoresis of Mr 28000 and 27000 (Abouzid & Jeske, 1986), corresponding to 82% of the particle weight. The mol. wt. of the coat protein predicted from the DNA sequence is 28000 (Frischmuth et al., 1990).

Genome Properties

The genome of AbMVa (the classical West Indian isolate) consists of two components (DNA-A and DNA-B; EMBL accession numbers X15983 and X15984) with different genetic information except for a 200 bp common region (Frischmuth et al., 1990; Fig.5). Transcription is bidirectional (Frischmuth et al., 1991) and produces polyadenylated mRNA. DNA-A replicates autonomously; DNA-B facilitates spread and is necessary for symptom formation (Evans & Jeske 1993a; 1993b). The double-stranded DNA intermediates form minichromosomes (Abouzid et al., 1988b; Pilartz & Jeske, 1992).

Relations with Cells and Tissues

Infection of Abutilon spp., Sida micrantha, Malva parviflora and Nicotiana benthamiana is confined to the phloem. Virus particles occur in tubular arrangements (Fig.6, Fig.7, Fig.8) or as loose aggregates in the nuclei of infected companion or phloem parenchyma cells (Jeske et al., 1977; Jeske & Schuchalter-Eicke, 1984; Abouzid et al., 1988a). Viral DNA has been detected both at these sites and in plastids (Gröning et al., 1987; 1990; Horns & Jeske, 1991). Cytopathological effects, especially degeneration of plastids, were observed in spongy and palisade parenchyma (Jeske & Werz, 1978; 1980b; Schuchalter-Eicke & Jeske, 1983; Jeske, 1986). Wound calluses and shoot-tip meristems are virus-free and can be used for the production of uninfected stock plants (Song & Jeske, 1994).

Notes

(i) Infective structures of AbMV, called "chains of pearls", have been described, (Jeske & Werz, 1980a). They contain viral DNA but it is unclear whether their protein is of viral or host origin. (ii) Abutilon sellovianum var. marmorata might be identical with A. pictum "Thompsonii" (syn. A. striatum "Thompsonii") (Macintosh et al., 1992) in modern systematic terms.

References

  1. Abouzid & Jeske, Journal of Phytopathology 115: 344, 1986.
  2. Abouzid, Barth & Jeske, Journal of Ultrastructure Research 99: 39, 1988a.
  3. Abouzid, Frischmuth & Jeske, Molecular and General Genetics 212: 252, 1988b.
  4. Abouzid, Polston & Hiebert, Journal of General Virology 73: 3225, 1992.
  5. Baur, Königliche Preussische Akademie der Wissenschaften 1: 11, 1906.
  6. Bird, Technical Paper, University of Puerto Rico Agricultural Experiment Station No. 26, 1958.
  7. Brierley, Plant Disease Reporter, Suppl. 150: 410, 1944.
  8. Costa, Phytopathologische Zeitschrift 24: 97, 1955.
  9. Costa & Bennett, Phytopathologische Zeitschrift 40: 266, 1950.
  10. Costa & Carvalho, Phytopathologische Zeitschrift 37: 259, 1960a.
  11. Costa & Carvalho, Phytopathologische Zeitschrift 38: 129, 1960b.
  12. Crandall, Plant Disease Reporter 38: 574, 1954.
  13. Evans & Jeske, Virology 194: 752, 1993a.
  14. Evans & Jeske, Virology 197: 492, 1993b.
  15. Flores & Silberschmidt, Phytopathologische Zeitschrift 43: 221, 1961/ 62.
  16. Flores & Silberschmidt, Phytopathology 53: 238, 1963.
  17. Flores & Silberschmidt, Anais da Academia Brasileira de Ciencias 38: 327, 1966.
  18. Flores & Silberschmidt, Phytopathologische Zeitschrift 60: 181, 1967.
  19. Frischmuth, Zimmat & Jeske, Virology 178: 461, 1990.
  20. Frischmuth, Frischmuth & Jeske, Virology 185: 596, 1991.
  21. Gröning, Abouzid & Jeske, Procedings of the National Academy of Sciences, USA 84: 8996, 1987.
  22. Gröning, Frischmuth & Jeske, Molecular and General Genetics 220: 485, 1990.
  23. Hertzsch, Zeitschrift für Botanik 20: 65, 1928.
  24. Höfer, Bedford, Markham, Jeske & Frischmuth, Virology 236: 288, 1997a.
  25. Holmes, in Bergey's Manual of Determinative Bacteriology, 6th edition, p. 1127, eds. R. S. Breed, E. G. D. Murray & A. P. Hitchens, Baltimore: Williams & Wilkins, 1948.
  26. Horns & Jeske, Virology 181: 580, 1991.
  27. Howarth & Vandemark, Journal of General Virology 70: 2717, 1989.
  28. Jeske, Journal of Phytopathology 115: 243, 1986.
  29. Jeske & Schuchalter-Eicke, Phytopathologische Zeitschrift 109: 353, 1984.
  30. Jeske & Werz, Phytopathologische Zeitschrift 91: 1, 1978.
  31. Jeske & Werz, Phytopathologische Zeitschrift 97: 43, 1980a.
  32. Jeske & Werz, Virology 106: 15558, 1980b.
  33. Jeske, Menzel & Werz, Phytopathologische Zeitschrift 89: 289, 1977.
  34. Keur, Bulletin of the Torrey Botanical Club 61: 53, 1934.
  35. Macintosh, Robinson & Harrison, Annals of Applied Biology 121: 297, 1992.
  36. Orlando & Silberschmidt, O Biologico 11: 139, 1945.
  37. Orlando & Silberschmidt, Archivos do Instituto Biológico, São Paulo 17: 1, 1946.
  38. Pilartz & Jeske, Virology 189: 800, 1992.
  39. Regel, in Gartenflora. ed. E. Regel, pp. 375, Stuttgart: Ferdinand Enke, 1868.
  40. Schuchalter-Eicke & Jeske, Phytopathologische Zeitschrift 108: 172, 1983.
  41. Silberschmidt, Archivos do Instituto Biológico, São Paulo 14: 105, 1943.
  42. Silberschmidt, Archivos do Instituto Biológico, São Paulo 16: 49, 1945.
  43. Silberschmidt, Phytopathology 38: 395, 1948.
  44. Silberschmidt & Tommasi, Anais da Academia Brasileira de Ciencias 27: 195, 1953.
  45. Silberschmidt & Tommasi, Annals of Applied Biology 44: 161, 1956.
  46. Silberschmidt, Flores & Tommasi, Phytopathologische Zeitschrift 30: 387, 1957.
  47. Smith, A Textbook of Plant Virus Diseases, 2nd edition, 1957.
  48. Song & Jeske, Journal of Phytopathology 140: 45, 1994.
  49. Höfer, Engel, Jeske & Frischmuth, Molecular Plant-Microbe Interactions 10: 1019, 1997b.
  50. Unseld, Ringel, Höfer, Höhnle, Jeske, Bedford, Markham & Frischmuth, Archives of Virology 145: 1449, 2000.
  51. Wege, Gotthardt, Frischmuth & Jeske, Archives of Virology, in press


Figure 1

Mosaic (variegation) in Abutilon sellovianum var. marmorata caused by a West Indian isolate (AbMVa). Photograph courtesy of Christina Wege.

Figure 2

Mosaic and stunting in Malva parviflora mechanically infected with the Brazilian isolate, AbMVb. Uninfected plant on left. Photograph courtesy of Christina Wege.

Figure 3

Mosaic in Sida micrantha caused by the Brazilian isolate, AbMVb.

Figure 4

Purified AbMVb particles after negative staining with uranyl acetate. Bar represents 100 nm.

Figure 5

Genome map of AbMVa (Frischmuth et al., 1990; 1991) showing ORFs AC1, AC2, AC3, AV1, BC1 and BV1, the common region CR, promotor structures (arrow heads), polyadenylation sites (P) and transcripts (thin line arrows). Reproduced by courtesy of Academic Press, Inc.

Figure 6

Companion cell of AbMVa-infected A. sellovianum var. marmorata showing cross-sections of tubular aggregates of geminivirus particles in the nucleus. Bar represents 1 Ám. Reproduced by courtesy of Paul Parey Verlag.

Figure 7

Nuclear tubules as in Fig.6 in longitudinal section. Bar represents 1 Ám. Reproduced by courtesy of Paul Parey Verlag.

Figure 8

Nuclear tubules as in Fig.7 at higher magnification showing that they are composed of twin particles. Bar represents 100 nm.