VIEW ARTICLE

Etiology

Purification and Some Properties of South African Isolates of Ornithogalum Mosaic Virus. J. T. Burger, Department of Microbiology, University of Cape Town, Private Bag, Rondebosch, 7700, South Africa, Permanent address: Vegetable and Ornamental Plant Research Institute, Private Bag X293, Pretoria, 0001, South Africa; M. B. von Wechmar, Department of Microbiology, University of Cape Town, Private Bag, Rondebosch, 7700, South Africa. Phytopathology 79:385-391. Accepted for publication 7 September 1988. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/Phyto-79-385.

Horticulturally important Ornithogalum and Lachenalia spp. were found to be infected with filamentous viruses. Symptoms in infected plants were similar to those produced by Ornithogalum mosaic virus (OMV). An enzyme-aided purification protocol was developed, which eliminated a highly viscous mucilage from extracts of both species. Serological tests indicated that virus isolates from Ornithogalum (OMV-O) and from Lachenalia (OMV-L) were indistinguishable. A morphologically similar virus, OMV-W, isolated from local symptom-bearing wild O. thyrsoides, was serologically closely related to OMV-O and OMV-L. Local isolates of OMV were serologically closely related to the Dutch isolate of OMV and were also related to several other potyviruses. Initial observations that OMV belongs to the potyvirus group were confirmed by biological and physicochemical characterization: the virus was mechanically transmissible to a restricted host range; it was nonpersistently aphid-transmitted; purified flexuous particles had a modal length in the range of 720–760 nm; a single major protein band of M_r 30,000 was observed after sodium dodecyl sulfate polyacrylamide gel electrophoresis; and an M_r of 2.90 × 10⁶ was calculated for OMV RNA after electrophoresis in denaturing formaldehyde agarose gels. Oligo (dT) cellulose chromatography confirmed that OMV RNA was polyadenylated.