Widespread occurrence of Tomato ring spot virus in deciduous fruit trees in Iran

Despite a long tradition of fruit-tree growing in all provinces of Iran, information on tree viruses in this country is scant. In the present study, presence of Tomato ring spot virus (ToRSV) was surveyed in various woody plants in this country by mechanical inoculation to herbaceous hosts, ELISA using a commercial antiserum, and PCR with specific primers. ToRSV was identified in the following plant-symptom combinations: Walnut with mottling, deformation, necrosis, and yellowing of main veins from Tehran Province; plum with yellowing of main veins, peach with yellowing of major veins and marginal necrosis, and hazelnut with interveinal chlorosis and marginal necrosis from Ardabil Province; apple with yellowing of main veins, mosaic and necrotic lesions, quince with large necrotic spots, and almond with leaf deformation and rosetting from Khorasan Province; and raspberry with marginal necrosis of leaf and necrotic lesions from Mazandaran Province. Mechanical inoculation from walnut, plum, peach, hazelnut, apple, quince, almond, and raspberry to Nicotiana tabacum cv. Samsun resulted in systemic infection. The virus isolates induced local lesions, leaf deformation, and necrosis in N. rustica, chlorotic local lesions on Chenopodium quinoa, and large local lesions on Gomphrena globosa. All samples were ELISA positive. PCR with specific primers resulted in the amplification of the expected fragment (490 bp). This study shows extensive occurrence of ToRSV in Iran.