B. Dikova and
N. Petrov, Nikola Poushkarov Institute of Soil Science, Agrotechnologies and Plant Protection, 7 Shosse Bankya Str., 1080 Sofia, Bulgaria; and
A. Djourmanski and
H. Lambev, Institute of Roses, Essential and Medical Cultures, 49 Osvobozhdenie Bld., 6100 Kazanluk, Bulgaria
The Siberian plant Leuzea carthamoides or maral root was introduced to Europe as a medicinal crop. Tomato spotted wilt virus (TSWV), genus Tospovirus, family Bunyaviridae, caused a harmful outbreak on L. carthamoides in central Bulgaria near the town of Kazanluk in 2009. In 2011, TSWV was identified on young sprouts from the rootages of L. carthamoides in the same place near the town of Kazanluk, Bulgaria, by means of indicator (test) 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 those L. carthamoides plants with such symptoms died in the second and third year. The number of the plants in the plantations decreased 20 to 40% during the 3-year period and some of these losses were from the virus disease except the environment conditions. DAS-ELISA was carried out with polyclonal TSWV antiserum of LOEWE Biochemica, GmbH, Germany. We obtained positive extinction values ODλ 405nm 0.358 ± 0.091 compared to the negative 0.053 ± 0.016 and the positive control 0.510 at a confidential interval at P ≤ 0.05. TSWV symptoms were observed on the following indicator plants according to Antignus et al. (1) and DPV/412 (2): Chenopodium quinoa, Cucumis sativus, Datura stramonium, Nicotiana glutinosa, N. rustica, N. tabacum cv. Samsun NN, and Petunia hybrida. TSWV caused on C. quinoa and on cotyledons of C. sativus cv. Delikates local chlorotic lesions only. In this TSWV differed from CMV because CMV caused systemic mosaic symptoms. Local small necrotic lesions and no systemic symptoms were observed on P. hybrida. We noticed systemic symptoms caused from TSWV on D. stramonium, N. glutinosa, N. rustica, and N. tabacum cv. Samsun NN. The systemic symptoms were chlorotic spots, concentric ring spots, and line patterns proceeding to necrosis. RT-PCR, adapted by Mumford et al. (3), was carried out on samples of L. carthamoides. Oligonucleotide primer sequences were used in accordance with Mumford et al. (3). 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 (marker 100 bp). The PCR fragment was sequenced and deposited to NCBI with GenBank Accession No. KC918808. PCR master mix without RNA template was used as a negative control. L. carthamoides is a newly established TSWV host in the world. To our knowledge, this is the first report of TSWV in L. carthamoides identified by RT-PCR.
References: (1) Y. Antignus et al. Phytoparasitica 25:319, 1997. (2) R. Kormelink. Descriptions of Plant Viruses, p. 412, 2005. (3) R. A. Mumford et al. J. Virol. Methods 57:109, 1996.