Study of viroids in hop plants and citrus plants, biological and molecular characterization of these viroids and formation of a gene bank

This study was carried out to determine the latest status of citrus viroid agents in citrus growing areas of Adana, Hatay, Mersin, Osmaniye between 2016-2019 and to investigate for the first time viroid disease agents in hops production areas in Pazaryeri districts of Bilecik province. In the other part of the study, identification and molecular characterization of the obtained isolates were performed. Within the scope of the study, all viroid pathogens found in citrus and hop plants were investigated with agent-specific primers. Respectively, were determined in the isolates examined by RT-PCR method. Citrus exocortis viroid (CEVd), Citrus bent leaf viroid (CBLVd), Hop stunt viroid (CVd II), CCaVd: Cachexia and HSVd: Non-Cachexia, Citrus dwarfing viroid (CDVd; CVd III), Citrus bark cracking viroid (CBCVd), Citrus viroid V (CVd-V), Citrus viroid VI (CVd-VI), Hop latent viroid (HLVd) and Hop stunt viroid (HSVd) were found on examined isolates. It was determined by RT-PCR analysis that the samples examined in terms of citrus viroids were 70% contaminated in Adana, 78% in Mersin, 77.5% in Hatay, and 80% in Osmaniye. In hop plants, 66% of 214 samples collected from Pazaryeri district of Bilecik were infected with HLVd and 23.8% with HSVd. Molecularly identified and sequenced isolates showed 96-99% similarity with the NCBI registered isolates. Sequences identified in this study were registered in the NCBI gene bank. HLVd was reported as the first record for our country.