Investigation and molecular characterization of viroid agents existance at Pospiviroid genus on tomato plant

This study was conducted to investigate viroid agents existance at Pospiviroid genus on tomato plant. For this purpose, between 2014-2015 years totally 400 tomato seeds, seedlings and leaves samples were collected and total nucleic acid extracts of these samples were obtained. In RT-PCR studies which were carried out by Pospi1-FW/RE and Vid-FW/RE semi-universal primer sets, any viroid infection was detected in 398 tomato samples. On the other hand, two tomato samples which were grown in flowerpot on ''Çeri'' cultivar, found infected with Citrus exocortis viroid (CEVd) by CEVd-FW/RE spesific primer pair. In agarose gel electrophoresis studies, 371 bp of DNA fragments were shown belong to these samples. CEVd infected tomato isolates were also characterized molecularly. Analysis of nucleotid aligments results showed % 89-98 sequence similiarity rates to some tomato, citrus and other plant species reported to NCBI Genbank database. In addition to molecular studies, to observe some different symptoms of Citrus exocortis viroid (CEVd) and Potato spindle tuber viroid (PSTVd) agents on tomato plants, a mechanical inoculation application was performed. First symptoms were pointed out approximately 30-35 days later from inoculation, for both viroid agents; as stunting, leaf epinasty, leaf curling and malformation of plant structure. Keywords: Viroid, Tomato, Pospiviroid, RT-PCR, Mechanical Inoculation