Molecular Diversity of Phytoplasmas Associated with Eggplant Phyllody Disease in Iran

During 2015–18, surveys were conducted in the main eggplant growing areas of Iran and in all areas phytoplasma-type symptoms were observed. A total of 350 symptomatic eggplant plants were collected and tested for the phytoplasma presence on 16S rDNA. Diversity of the detected phytoplasmas was verified by molecular analyses, dodder and graft transmission on experimental test plants. Phytoplasmas were detected in all symptomatic samples and, by using nucleotide sequence comparisons and virtual restriction fragment length polymorphism analyses of 16S rDNA, six subgroups including 16SrII-D and -V, 16SrIX-C and -I, 16SrVI-A and 16SrXII-A and molecular variants related to 16SrII-D, 16SrVI-A, 16SrIX-C subgroups were identified. Based on symptomatology in dodder and graft inoculated eggplant and periwinkle plants, the phytoplasmas enclosed in the identified subgroups were differentiable. Collectively, based on the results of the present study and considering the reported presence of phytoplasmas belonging to the same ribosomal subgroups in other crops, eggplant fields play an important role in the epidemiology of other diseases associated with these phytoplasmas in Iran.