New indicator plants for potato virus X.

For over 2 years (2002-2004); a sever virus like disease on leaves in Pisum sativum was observed from Tehran in Iran. The identity of which was established by the following host reactions and serological and molecular assays. Collected samples were tested for the presence of the virus using the DAS-ELISA (direct double antibody sandwich-ELISA). Leaf sap of each test samples was diluted 1:10 in ELISA sample buffer. The samples reacted in ELISA with antibody against Potato virus (x)(PVX). The samples were passed through three single chlorotic local lesion transfers on Gompherena globosa, which showed chlorosis 5 to 7 days after mechanical inoculation. Finally one local was homogenized in phosphate buffer (0.05 M, pH 7.2) and rubbing the inoculums on carbourundum--dusted leaves of Nicotiana glutinosa. For host range studies extracts prepared from infected N. glutinosa leave were inoculated to the 35 species. The virus induces systemic mosaic symptoms on Petunia hybrida, Physalis floridana, Nicandera physaloides and Solanum nigrum. This has not been yet record as assay hosts for PVX. Total RNA extracted from symptomatic, plants and RNA extracted from purified virus preparations were tested using reverse transcription polymerase chain reaction (RT-PCR) with specific primers designed to amplify a fragment of the RNA-dependent RNA-polymerase gen. Back inoculation from different symptomatic plants, had been done to Pisum sativum and confirmed by DAS-ELISA. This is the first report of Petunia hybrida, Physalis floridana, Nicandera physaloides and Solanum nigrum as new indicator plants for PVX.