DETECTION OF MULTIPLE VIRUSES IN VERBENA, DIASCIA AND LOBELIA PLANTS
Several plants from 2 varieties each of Verbena (Temari Bright Pink and Ron Deal), Diascia (Hannah Rose and Red Ace), and Lobelia (Tioga Blue and Laguna) were obtained from a local nursery (EuroAmerican Propagators, Bonsall, CA) showing various symptoms including mosaic and ringspots. Double-stranded (ds) RNAs were extracted from each plant to look for the presence of the replicative forms of possible ssRNA plant viruses. Multiple dsRNAs were found in each host ranging in size from approximately 10,000 nt to 300 nt, with some varieties sharing dsRNAs of similar size. Some plants appeared to contain infections of multiple viruses. Tissue from each plant was also used to inoculate a series of host range plants. One species of tobacco, Nicotiana clevelandii was especially susceptible to infection by extracts from most of these ornamental species. After several virus purifications from the two Diascia varieties and Verbena Ron Deal plants, we have identified the presence of a tymovirus based on sucrose density gradient profiles, number and sizes of ssRNAs within the purified virions, and the size of the coat protein. These plants had been preliminarily identified by another laboratory as being infected with Scrophularia mottle tymovirus (ScrMV), however we were unable to obtain symptoms in Datura stramonium plants, a known host for ScrMV, so the specific tymovirus present is currently unknown. Other potential viruses have not yet been identified. The tymovirus is dominant in titre and additional host range analysis is underway in order to separate the other viral components into pure infections for further study. Purified virus preparations from the Diascia Red Ace plants were used to produce a polyclonal antibody. Immunodiffusion tests showed the antibody reacted against the original antigen as well as sap from infected Diascia and Verbena plants.
Mathews, D.M. and Dodds, J.A. (2006). DETECTION OF MULTIPLE VIRUSES IN VERBENA, DIASCIA AND LOBELIA PLANTS. Acta Hortic. 722, 219-228