VIEW ARTICLE

Etiology

Properties and Cytopathology of a Tymovirus Isolated from Eggplant. V. B. V. de Souza, Department of Plant Pathology, University of Arkansas, Fayetteville 72701; R. C. Gergerich, K. S. Kim, and M. A. C. Langham. Department of Plant Pathology, University of Arkansas, Fayetteville 72701. Phytopathology 80:1092-1098. Accepted for publication 26 April 1990. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/Phyto-80-1092.

An isometric virus measuring 28 nm was isolated from eggplant (Solanum melongena) and mechanically transmitted to several species of the families Amaranthaceae, Chenopodiaceae, Labiatae, and Solanaceae. The virus was vectored by the flea beetle, Epitrix fuscula. Ultrastructural studies showed that chloroplasts of infected plants were clustered and formed tymovirus-characteristic double membrane-bound vesicles. In Nicotiana rustica, immunogold labeling studies showed that the largest numbers of virus particles were in the cytoplasm and vacuole of infected cells. Purified virus formed two bands in CsCl and sucrose gradients. The capsid contained a single polypeptide of about 24 kDa; RNase digested the nucleic acid, which had a molecular weight of 2.0 ? 10⁶ Da. The virus particles had one positively charged electrophoretic form, as demonstrated by migration toward the cathode during agarose electrophoresis. The virus is serologically related to tymoviruses of the subgroup of eggplant mosaic virus (EMV) and could not be distinguished from Abelia latent strain (EMV-AL). Several differences, however, were found in the studies of host range and symptomatology of these two strains. These differences and some other properties of the Arkansas isolate of EMV are reported in this paper.