گزارش ویروس پژمردگی لکه‌ای گوجه‌فرنگی (TSWV) از گیاه دارویی سرخارگل (Echinacea angustifolia)

Tomato spotted wilt virus (TSWV) is the type member of genus Orthotospovirus in the family Tospoviridae with a spherical body and a negative-sense, single-strand RNA genome. It is divided into three segments termed S, M, and L. The M and S RNA segments encode for proteins in an ambisense direction. This virus is one of the most economically devastating plant viruses in agricultural products and has a wide range of hosts, so that it causes disease in more than 35 families of plants. The circulative propagative transmission of TSWV is carried out by at least ten different species of thrips. During the visit to the farm of faculty of agriculture and environment, Arak University, symptoms of TSWV were observed in Echinacea angustifolia. Echinacea angustifolia is a perennial herbaceous plant of the family Asteraceae. The hydroalcoholic root extract of the plant is rich in phenols and flavonoids, two components that have been shown to increase antioxidant activity in organisms. Plants with symptoms of yellow or brown ring spots and black streaks on the leaves, as well as signs of necrosis on the leaves were sampled. In order to detect TSWV in samples, molecular identification of infected samples was performed by RT-PCR in the laboratory. Total RNA was extracted from using RNX-plus kit (Cinnagen, Iran) and was used in reverse transcription polymerase chain reaction (RT-PCR) using TSWV- specific primer pair to amplify a segment of N protein gene. A fragment with 777 bp in length was amplified. The amplified fragment inserted into T/pTZ57R vector and transformed into E.coli strain DH5α. The recombinant plasmid was extracted and analyzed by restriction enzymes and then sequenced. Nucleotide sequence of the amplicon was compared with the previously reported TSWV isolates using Blast software, which revealed the highest identity as of 97%-88% at both nucleotide and amino acid levels. To our knowledge, this is the first report of TSWV on medicinal plants in Iran.