Molecular Analysis of 'Candidatus Phytoplasma trifolii' and 'Candidatus Phytoplasma solani' Associated with Phytoplasma Diseases of Tomato (PDT) in Turkey

Tomato plants displaying severe fruit deformation, flower sterility, aerial rooting, purplish leaves and leaf rolling were observed in tomato fields at Van province (Turkey). Samples were collected, and total DNA was extracted from symptomatic and asymptomatic plants. Nested polymerase chain reaction (nested-PCR) assays were performed to amplify 16S rDNA sequences for molecular detection using universal primer pairs. Out of 100 tested tomato samples, 11% of tomato samples yielded a DNA fragment of 1.25 kb. Amplified PCR products were then cloned into pGEM T-Easy vector and sequenced using new generation DNA sequencing (NGS) system. The virtual restriction fragment length polymorphism (RFLP) analysis of 16S rDNA sequences and molecular detections were allowed to characterize possible phytoplasmas associated with diseased plants. Our results revealed the presence of two Phytoplasma species belonging to two different ribosomal groups; 'Candidatus Phytoplasma trifolii' (16Sr VI-A group) (Acces no. MF564268, MG732925) and 'Candidatus Phytoplasma solani' (16SrXII-A group) (Acces no. KY579358, MF576263). Despite a high variation in their similarity coefficient of'Ca. P. solani' VTS2 (0.91) and 'Ca. P. trifolii' VTT1 (0.88) isolates, the infected tomato plants generally displayed similar disease symptoms during field observations. Due to its commercial interest, co-existing of these phytoplasmas in tomato fields is of great phytosanitary significance not only for tomato plants but also for other crops such as vegetables, ornamentals and field crops. With this study, 'Ca. P. trifolii' associated with phytoplasma diseases of tomato (PDT) has been reported for the first time in tomato in Turkey. (C) 2018 Friends Science Publishers