Turkey is one of the main globe artichoke (Cynara cardunculus L. subsp. scolymus (L.) Hayek) producers in the world. Cultivation of this crop is done mainly in the Aegean and Eastern Marmara regions with asexually propagated cultivars such as Bayrampasa and Sakiz. More than half of total globe artichoke production in Turkey is obtained from the provinces of Izmir, Aydin, and Mugla in the Aegean region. Surveys in 2011 and 2012 were carried out to look for the presence of Artichoke yellow ringspot virus (AYRSV), Tobacco mosaic virus (TMV), and Tomato spotted wilt virus (TSWV) in the globe artichoke production areas in these three provinces. Double antibody sandwich (DAS)-ELISA and reverse transcriptase (RT)-PCR assays conducted for TMV and TSWV showed that the samples were not infected with these two viruses. Due to the lack of commercial ELISA kits against AYRSV, RT-PCR and biological indexing were used for its identification. Leaf tissues from 35 symptomatic and 25 symptomless plants were sampled and analyzed by RT-PCR using as template total RNAs extracted by a silica gel method (1). RT-PCR was conducted as previously reported (1). A PCR product of the expected size (about 530 bp) was obtained from five plant samples that were collected from Izmir province and had symptoms of bright yellow spots and line patterns on the leaves. The incidence of diseased plants in the fields ranged from 1 to 5%. In previously conducted studies, these symptoms were defined as typical symptoms of AYRSV on artichokes (2,3,4). One of the PCR products was cloned and sequenced. BLASTn analysis of the obtained sequence (GenBank Accession No. KC622054) showed 92% nucleotide identity with the partial RNA1 sequence of an AYRSV isolate from Allium cepa (AM087671.2). Furthermore, selected test plants were mechanically inoculated with sap from plant samples that were positive in RT-PCR. Chlorotic local lesions and systemic mottling symptoms were observed on Chenopodium quinoa; chlorotic lesions, mosaic, and deformation on Cucumis sativus; and systemic mosaic, reddish necrotic local lesions, and malformation on Phaseolus vulgaris (French bean). Results of the biological tests were confirmed by RT-PCR. AYRSV has a wide host range including artichoke and six other cultivated plant species and can be easily transmitted by seed, plant sap, and vegetative propagation (3). To our knowledge, this is the first report of natural infection of globe artichoke by AYRSV in Turkey. AYRSV infections can have a detrimental effect on the growth and yield of artichoke plantings. This assay will be useful for further epidemiological studies.
References: (1) X. Foissac et al. Acta Hortic. 550:37, 2001. (2) D. Galliitelli et al. Adv. Virus Res. 84:289, 2012. (3) P. E. Kyriakopoulou et al. Ann. Inst. Phytopathol. Benaki 14:139, 1985. (4) V. I. Maliogka et al. Phytopathology 96:622, 2006.