Detection and Identification of Tomato Ring Spot Virus in Ornamental Plants in North Khorasan Province

In recent years, the symptoms of viral diseases such as dwarfism, mosaic, discoloration, necrosis, and circular spots have been prevalent in ornamental plants in parks, gardens, and streets in North Khorasan Province. Tomato ring spot virus (ToRSV) belongs to the Nepovirus genus of Secoviridae family. This virus is a major cause of the infection of ornamental plants in the world. In this study,  to evaluate the percentage of  infection to ToRSV, in the early autumn of  2014,  400  samples of  ornamental plants were collected based on the suspicious viral symptoms from parks, gardens, and streets of  North  Khorasan  province (Bojnord  and Shirvan Cities) and were transported to the laboratory in cold conditions. In the laboratory, DAS-ELISA serological test was performed to evaluate the presence of virus in the suspected samples. Then, the infected samples identified by ELISA test were inoculated to the test plants of Cucumis sativus L. (Cucumber), Vigna unguiculata L. (Cowpea) and Nicotiana glutinosa L. (Tobacco). After the appearance of symptoms, in order­ to verify the infection, they were tested  again using DAS-ELISA. The molecular identification of the infected samples was done by Qiagene RNA extraction kit. Using specific primers in RT-PCR reaction, a fragment was amplified in the band of 449bp. The results of DAS-ELISA and RT-PCR tests proved the presence of the virus on ornamental plants in North Khorasan Province. In the mechanical inoculation of the virus, three above-mentioned plants showed the symptoms of the disease.