Molecular Detection of Non-necrogenic Satellite RNA of Cucumber Mosaic Virus

Association of satellite RNA with Cucumber Mosaic Virus (CMV) leads to either attenuation or enhancement of the viral symptoms. For detection of the satellite RNAs in Iranian isolates of CMV, plant samples showing viral symptoms were collected from different farms in the provinces of East- and West- Azerbayjan and Ardebil. These samples were inoculated onto the experimental host plants in greenhouse with the virus being detected using common serological methods. To study the possible effects of the satellite RNA on symptoms of CMV, biological purifications were performed using local lesion and propagation hosts. One pair of primers, specific to the coat protein coding region of the virus was employed to detect CMV. Based on the behavior of CMV isolates on the test plants, especially on N.tabacum cv. Samsun on which the satellite RNA causes chlorosis, N.rustica, and also on tomato, seven isolates were found and designated as a group of the virus variants that cause chlorosis on N.tabacum cv. Samsun. For detection of the satellite RNA, a PCR product of about 360bp was amplified using a pair of specific primers(CMV-Sat –F and Sat-R) from one of the isolates. Several inoculations on tobacco and on tomato plants showed the possible presence of the satellite RNA attenuated CMV symptoms on the host plant, the characteristic of non-necrogenic Satellite RNAs. This is the first report from Iran on the possible presence of satellite RNA in CMV isolates.