First report of Tomato spotted wilt virus on a new host Leuzea carthamoides in Bulgaria and the World.
Tomato spotted wilt virus (TSWV) caused a harmful outbreak on L. carthamoides [Rhaponticum carthamoides] in central Bulgaria near the town of Kazanluk in 2009. In 2011, TSWV was identified on young sprouts of the rootages of L. carthamoides in the same place near the town of Kazanluk by means of indicator plants, double antibody sandwich (DAS)-ELISA, and reverse transcription (RT)-PCR. Disease symptoms were small yellow spots on the young leaves grown from the tested sprouts and distortions of the leaf lamina. The old leaves had large yellow spots and necrosis, without deformations. Most of the plants with such symptoms died in the second year and third year. The number of the plants in the plantations decreased by 20-40% during the 3-year period and some of these losses were due to the viral disease. RT-PCR was carried out on samples of L. carthamoides using oligonucleotide primer sequences. The DNA fragment was visualized by UV trans-illumination. A fragment of the TSWV genome with a length of 276 base pairs was found in three young L. carthamoides leaf samples taken from the sprouts. The PCR fragment was sequenced and deposited to NCBI (GenBank Accession No. KC918808). This is thought to be the first report of TSWV in L. carthamoides identified by RT-PCR.