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First Report of ‘Candidatus Phytoplasma solani’ Infecting Garden Bean Phaseolus vulgaris in Serbia

    Authors and Affiliations
    • M. Mitrović
    • T. Cvrković
    • J. Jović
    • O. Krstić
    • M. Jakovljević
    • A. Kosovac , Institute for Plant Protection and Environment, Department of Plant Pests, Banatska 33, 11080 Zemun, Serbia
    • I. Toševski , Institute for Plant Protection and Environment, Department of Plant Pests, Banatska 33, 11080 Zemun, Serbia; CABI, 1 Rue des Grillons, 2800 Delémont, Switzerland.

      Geographic spread of ‘Candidatus Phytoplasma solani’ belonging to the 16SrXII-A ribosomal subgroup has been reported over the past decade in different crops in Serbia (2). In August 2014, six garden bean plants (Phaseolus vulgaris L.) with symptoms of discoloration, yellowing, and downward rolling of the leaves were sampled from Stara Pazova in Syrmia District of Vojvodina, northwestern Serbia. Six asymptomatic plants were also collected as controls. PCR analysis using P1/P7 and R16F2n/R16R2 primers, followed by restriction fragment length polymorphism with MseI (5) was conducted for initial phytoplasma detection. Comparison of the 16S rRNA restriction profiles of isolates with reference strains identified them as ‘Candidatus phytoplasma solani.’ All control beans tested negative. Characterization of stolbur phytoplasma, based on the stamp gene was done using StampF/R0>StampF1/R1 primers (3), and sequenced data was deposited in GenBank under Accession No. KM977907. The stamp gene sequences showed 100% identity with the reference strain Rqg50 (KC703019), previously reported in grapevine, Reptalus quinquecostatus and R. panzeri, in Serbian vineyards (2). From all stolbur-positive samples, a fragment of the vmp1 gene was amplified using StolH10F1/R1 (1) and TYPH10F/R (4) and digested with RsaI. Restriction profiles of the vmp1 gene from all six isolates were the same as the V14 vmp1 type, a reference profile of stolbur phytoplasma reported in association with grapevine in Serbia. According to the collective vmp1/stamp typing, the stolbur phytoplasma found in the garden bean samples belongs to genotype V14/Rqg50, which corresponds to the genotype Rqg50g infecting grapevine in North Serbia. This finding represents the first report of stolbur phytoplasma associated with garden beans in Serbia and South Eastern Europe. The garden bean is an important crop in Serbia. Considering the complexity of the stolbur phytoplasma epidemiological cycles in other vegetable crops, this finding highlights the urgent need for further surveys of the disease to establish its incidence and impact on bean production and its propagation pathways for the purpose of developing management strategies.