Identification and molecular characterization of tomato spotted wilt virus (TSWV-RB) resistance breaking isolates through natural hosts in Antalya province

The study was carried out in a pepper and tomato greenhouse in Antalya, in the coastal (Serik) and highland region (Elmalı). Cultivated plants and weeds were sampled in the survey areas and the presence, prevalence and races of Tomato spotted wilt virus (TSWV) were investigated by biological, serological (DAS-ELISA test) and molecular tests (RT-PCR, qRT-PCR) and a screening was performed for the isolate that broke resistance. A total of 270 weeds and 112 different plant species (tomato, pepper, eggplant, lettuce, bean, corn, okra, chard, parsley) were tested. As a result of serological studies, various symptoms such as mosaic, chlorotic spots, yellowing, deformity, stunting and feeding traces of thrips were observed on the leaves of some weeds infected with the virus, while no symptoms were observed in some infected weeds. Of the 39 weed species tested, 19 were infected with the disease. The highest rate of infestation was found in the Asteraceae family and Sonchus asper (L.) species, followed by the Poaceae and Solanaceae families, respectively. The strain of the virus in the infected weeds was determined as a result of qRT-PCR and melt-curve analysis using a special primer pair designed during the study and the isolate that does not break resistance in tomato (TSWV-NRB). As a result of the comparison of the isolates, two different Tm values were determined, and these findings were confirmed by the sequence data, revealing that the kit, protocol and primers used constitute a fast and reliable diagnostic kit without the need for sequencing service in identifying the isolates that break the Sw-5 resistance.