اولین گزارش از همراهی یک فیتوپلاسما از گروه 16SrVI با بیماری جاروک کنار

Christ's thorn jujube (Ziziphus spina-christi) is one of the tropical trees in southern regions of Iran. In February 2022, symptoms similar to phytoplasma-associated diseases was observed in a Christ’s thorn jujube seedling in the green space of Bandar abbas (Hormozgan province, Iran). The symptomatic seedling showed witches broom, plant stunting (shortened internodes), yellowing and little leaf. To identify association of phytoplasma with the symptomatic seedling, total genomic DNA was extracted from 0.2 g midribs using modified cetyltrimethylammonium bromide (CTAB) method. The samples were analyzed for phytoplasma DNA by direct-PCR using the phytoplasma universal primer pair Rl6mF2/R16mR1. Fragments of expected size (1434 bp) were amplified with direct PCR in sample of symptomatic plant but not in sample of symptomless plant or sterile distilled water as negative controls. A positive PCR product was directly sequenced and deposited in GenBank under accession no. OM964913. A BLAST search using sequenced fragment confirmed the phytoplasma infection and showed that the phytoplasma associated with Christ's thorn jujube witches' broom (CjWB) had 100 % nucleotide identity with the corresponding sequence of several members (MK660149, KP119494 and KP864671) of the 16SrVI phytoplasma group, Candidatus Phytoplasma trifolii. Virtual restriction fragment length polymorphism with iPhyClassifier software revealed that CjWB phytoplasma belonged to 16SrVI-A subgroup. To our knowledge, this is the first report of natural infection of Christ's thorn jujube by phytoplasma disease. Phytoplasmas belonging to the 16SrVI-A have been previously reported on several vegetable crops such as tomato and on rapeseed in Hormozgan. Due to the abundance of Christ's thorn jujube trees near commercial fields in southern Iran, these trees may act as an reservoir host for this phytoplasma.