Occurrence of Turnip mosaic virus on ornamental crops in Iran

During the summer of 2003, plants grown in 7 commercial greenhouses in the Markazi province of Iran showed the following symptoms: chlorotic spots, mosaic, vein yellows and stunting on Petunia hybrida; mottling on Chrysanthemum sp.; chlorotic spots, leaf yellows and black stem streaks on Impatiens balsamina; mottling, leaf yellows and malformation on Cheiranthus cheiri; mosaic and colour breaking on Matthiola sp. and Zinnia elegans. When sap from symptomatic leaves was used for mechanical inoculation, necrotic local lesions, followed by systemic and top necrosis symptoms, were produced on Nicotiana glutinosa, in addition to mosaic symptoms on P. hybrida and Brassica rapa. The collected leaf samples and the inoculated plants were tested for Turnip mosaic virus (TuMV) by DAS-ELISA using specific polyclonal antibodies (kindly provided by S. Winter, DSMZ, BBA Messeweg 11/12, D-38104 Braunschweig, Germany). ELISA tests confirmed the presence of TuMV in both the original leaf samples and inoculated indicator plants. Transmission electron microscopy showed flexuous filamentous particles approximately 720-730 nm in length in leaf extracts of the plants sampled. In addition, two fragments of the expected size, approximately 700 bp and 1700 bp, were amplified using RT-PCR and universal primers for potyviruses (Gibbs & Mackenzie, 1997). TuMV has previously been reported from Iran on stock plants (Matthiola sp.) and oilseed rape (B. napus) (Bahar et al., 1985; Shahraeen et al., 2003). However, this is the first report of the natural occurrence of TuMV on C. cheiri, Chrysanthemum sp., I. balsamina, P. hybrida and Z. elegans in Iran.