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Etiology

Ultrastructural Studies of Jatropha gossypifolia Infected with Jatropha Mosaic Virus, a Whitefly-Transmitted Geminivirus. K. S. Kim, Department of Plant Pathology, University of Arkansas, Fayetteville 72701; J. Bird(2), R. L. Rodriguez(3), E. M. Martin(4), and J. Escudero(5). (2)(3)(5)Agricultural Experiment Station, University of Puerto Rico, Rio Piedras; (4)Department of Plant Pathology, University of Arkansas, Fayetteville 72701. Phytopathology 76:80-85. Accepted for publication 6 August 1985. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/Phyto-76-80.

Plants of Jatropha gossypifolia of various ages infected with Jatropha mosaic virus via the whitefly. Bemisia tabaci, were studied ultrastructurally. Leaves with typical symptoms exhibited the nucleopathic effects that are characteristic of known whitefly-transmitted geminiviruses. Electron-dense fibrillar bodies occurred at an early stage of infection and were closely associated with viruslike particles at a late stage of infection. Many fibrillar bodies were ring-shaped and consisted of orderly aligned spherical 'beads' of high electron density embedded in a less electron-dense fibrillar matrix. Cytochemical studies indicated that the fibrillar bodies are DNA-containing structures. Cytoplasmic inclusions (membrane-bound oval bodies containing granular and/or fibrillar material) also were observed. The central cavity of the ring-shaped fibrillar bodies was often filled with material similar to those of the cytoplasmic inclusions. Viruslike particles, 15-18 nm in diameter, occurred only in the nuclei and mature sieve elements. The infection appeared to be limited to phloem cells. It is suggested that Jatropha mosaic disease is caused by a whitefly-transmitted geminivirus.