An Identification and Evaluation of the Distribution of Tomato Ringspot Virus (ToRSV) of Stone Fruits, in Golestan and Fars Provinces, Iran

Tomato ringspot virus (ToRSV) is a member of the genus Nepovirus, family Secoviridae, causing substantial economically declining in perennial crops, including stone fruits, worldwide. During the years 2008 and 2009 a total number of 414 symptomatic and asymptomatic leaf samples were randomly collected from different stone fruit trees including peach, apricot, plum and sour cherry from Fars and Golestan provinces. Applying DAS-ELISA method samples were tested for the presence of ToRSV, through specific polyclonal antibody. Serological tests revealed that, during the years 2008 and 2009, different stone fruits were infected with ToRSV, with the infection rates of 8.5% and 10.2% in gardens of Fars and in Golestan with respective infection rates of 30% and 23.1%. One hundred of different stone fruit leaf samples that had weakly reacted with ToRSV antibody in DAS-ELISA test, were tested again through Dot- immunobinding assay (DIBA), ToRSV infection being confirmed in 85 samples. For an evaluation the biological properties of the detected isolates, they were subjected to mechanical inoculation on herbaceous plants and the morphology of isometric viral particles observed through immunosorbent electron microscopy for apricot and peach samples. According to the host range study the Iranian isolates did not differe in biological properties from other isolates. Such Symptoms as necrotic ring spots and leaf mosaics were frequently related to the viral infection. Applying with RT-PCR, a DNA fragment of 499 bp, belonging to the coat protein coding sequence of the ToRSV genome, was amplified for 20 out of 30 peach, apricot, plum and sour cherry samples the samples were serologically tested as positive to ToRSV infection. Results proved that different stone fruits in some gardens in South and Northern parts of Iran are infected with ToRSV.