Details of DPV and References
DPV NO: 107 October 1972
Species: Cocksfoot mild mosaic virus | Acronym: CMMV
Cocksfoot mild mosaic virus
W. Huth Biologische Bundesanstalt für Land- und Forstwirtschaft, Institut für landw. Virusforschung, Braunschweig, Germany
H. L. Paul Biologische Bundesanstalt für Land- und Forstwirtschaft, Institut für landw. Virusforschung, Braunschweig, Germany
- Main Diseases
- Geographical Distribution
- Host Range and Symptomatology
- Transmission by Vectors
- Transmission through Seed
- Transmission by Grafting
- Transmission by Dodder
- Nucleic Acid Hybridization
- Stability in Sap
- Properties of Particles
- Particle Structure
- Particle Composition
- Properties of Infective Nucleic Acid
- Molecular Structure
- Genome Properties
- Relations with Cells and Tissues
- Ecology and Control
Huth (1968) and
Huth, Brandes & Paul (1970).
- Mildes Mosaik des Knaulgrases (Rev. appl. Mycol. 48: 507)
An RNA-containing virus with isometric particles 25 to 30 nm in diameter. It is readily transmissible by sap inoculation, whereas transmission by the aphid Myzus persicae is poor. It infects species in the Gramineae only, and is widespread in the German Federal Republic.
Causes mild mosaic in most naturally infected hosts.
Found in the German Federal Republic.
Host Range and Symptomatology
Infected 24 out of 37 species of Gramineae, but none of 8 species of
or Aizoaceae. The host plant found naturally infected was Dactylis glomerata.
Initial symptom is chlorotic mottle followed by
systemic necrosis and death.
In addition to the type strain, two other strains have been found in Lolium perenne and Festuca pratensis respectively; these species are immune to the type strain (W. Huth, unpublished).
Transmission by Vectors
The virus is transmitted inefficiently by the aphid Myzus persicae. Possible vectors of other kinds were not tested.
Transmission through Seed
Transmission by Dodder
The virus is strongly immunogenic; antisera with titres of 1/1024 in agar gel double diffusion tests are easily obtained.
The virus is serologically related to phleum mottle virus and resembles it in some other properties (Paul & Huth, 1970 and unpublished; R. Bercks & G. Querfurth, unpublished). The degree of relatedness is not yet determined. Surprisingly, both viruses show a very distant serological relationship to tobacco mosaic virus and related viruses; furthermore, a very distant relationship was found between cocksfoot mild mosaic virus and viruses of the turnip yellow mosaic virus group (Bercks & Querfurth, 1971 and unpublished).
Stability in Sap
In crude leaf extracts of Setaria italica the thermal inactivation point (10 min) is 80-85°C; the dilution end-point is c. 5 x 10-5; and infectivity is retained at -20°C for up to 5 years.
The virus is stable and occurs in high concentration in sap of Setaria italica, from which it is easily purified by adding n-butanol to 8% (v/v) allowing the mixture to stand overnight at 4°C and removing the insoluble material. The virus is further purified and concentrated by several cycles of differential centrifugation.
Properties of Particles
Sedimentation coefficient (s20,w) at infinite dilution 105±1 S (determined at both pH 7.2 and 6.6).
Molecular weight (daltons): c. 5.5 x 106.
Diffusion coefficient (D20,w x 10-7 cm2 sec-1): c. 1.5.
Partial specific volume (calculated): 0.69-0.70 ml/g.
Electrophoretic mobility: in 0.002 M Tris, 0.1 M H3BO3, 0.001 M disodium ethylenediamine-tetraacetate, pH 7.8, the virus migrates rapidly as one band towards the anode.
A260/A280: 1.62±0.02, corrected for light-scattering.
The particles are isometric, 25-30 nm in diameter (Fig. 3). Some particles seem to have a hexagonal outline. No empty particles are evident, but penetration by the stain is variable.
RNA: Molar percentages of bases (±0.3): G26.6; A23.4; C28.4; U21.6. RNA content of particles c. 23.5%.
Protein: the subunits have a M. Wt of 24,900 (H. L. Paul, unpublished).
Relations with Cells and Tissues
The only known spherical viruses occurring in cocksfoot are cocksfoot mild mosaic and cocksfoot mottle. These can be distinguished by host plants, serology and some particle properties (Catherall, 1970).
Cocksfoot mild mosaic and phleum mottle viruses are serologically related, but they have distinct host ranges: the type strain of cocksfoot mild mosaic virus does not infect Phleum pratense and phleum mottle virus does not infect Dactylis glomerata.
Photographs courtesy of Biologische Bundesanstalt, Braunschweig.
References list for DPV: Cocksfoot mild mosaic virus (107)
- Bercks & Querfurth, Phytopath. Z. 72: 354, 1971.
- Catherall, CMI/AAB, Descriptions of Plant Viruses 23, 3 pp., 1970.
- Huth, Phytopath. Z. 62: 300, 1968.
- Huth, Brandes & Paul, Phytopath. Z. 68: 367, 1970.
- Paul & Huth, Phytopath. Z. 69: 1, 1970.