Molecular diversity of phytoplasmas associated with eggplant phyllody disease in Iran

Abstract

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.Phytoplasmas are associated with different destructive plant diseases worldwide (Bertaccini et al., 2014) and are transmitted mainly by leafhoppers, however they could be disseminated also by propagation materials and in several cases by seeds (Satta et al., 2019). Phytoplasma presence is associated with symptoms of yellowing, discoloration, witches' broom, dwarfing, virescence, and phyllody. More than 1000 plant species from different plant families are reported as affected by phytoplasmas (Bertaccini & Duduk, 2009;Lee et al., 2000) and among them, vegetables growing in the major production areas worldwide, are infected by phytoplasmas belonging to numerous ribosomal groups (Kumari et al., 2019). In particular, eggplant (Solanum melongena L.) was reported as infected with strains belonging to 16SrI in Japan, Bangladesh and India

Eggplant Little Leaf-Associated Phytoplasma Detection in Seedlings under Insect-Proof Conditions

“…The identified phytoplasmas belong to the groups 16SrI (aster yellows), 16SrII (peanut witches' broom), 16SrIII (X-disease), 16SrV (elm yellows), 16SrVI (clover proliferation), 16SrXII ("stolbur") and are reflecting the phytoplasmas identified so far in this plant species. The phytoplasmas most frequently identified in eggplants showing little leaves in India belong to the 16SrVI-D and 16SrII-D subgroups [10,55] and this result is confirmed by the detection of both phytoplasmas in first-generation seedlings. However, other ribosomal groups are associated with the little leaf of brinjal throughout the world; in particular, several subgroups and variants were recently reported from Iran by using nucleotide sequence comparisons and virtual RFLP analyses.…”

Brinjal Little Leaf Disease Epidemiology in Insect Proof Conditions

“…There are other ribosomal groups associated with the little leaf of brinjal throughout the world, in particular, several subgroups and variants were recently reported from Iran, by using nucleotide sequence comparisons and virtual RFLP analyses. In particular several subgroups including 16SrI, 16SrII-D and 16SrII-V, 16SrIII-J and16SrIII-U, 16SrIX-C, 16SrVI-A and 16SrXII-A, and molecular variants related to 16SrII-D, 16SrVI-A, 16SrIX-C subgroups were reported [53].…”