A. R. Golnaraghi, Department of Plant Protection, College of Agriculture and Natural Resources, Science and Research Branch, Islamic Azad University (IAU), P.O. Box 14515-775, Tehran, Iran; and
S. Yazdani-Khameneh, and
T. S. Khosroshahi, Scientific Association of Plant Protection, Science and Research Branch, IAU, Tehran, Iran
Tospoviruses are considered one of the most devastating viruses in different crops and ornamentals worldwide. There have been increasing records of the natural occurrence of Tomato yellow fruit ring virus (TYFRV) in Iran (e.g., 1,2,3), a recently proposed species in the genus Tospovirus (4). During the growing seasons 2010 to 2011, surveys were conducted in pepper fields (Capsicum annum) in Tehran province, one of the main vegetable producing areas of Iran, to detect the presence of tospovirus species infecting this crop, including Groundnut ringspot virus (GRSV), Impatiens necrotic spot virus (INSV), Iris yellow spot virus (IYSV), Tomato chlorotic spot virus (TCSV), Tomato spotted wilt virus (TSWV), TYFRV, and Watermelon silver mottle virus (WSMoV). Overall, 14 fields were surveyed and 119 pepper leaf samples from plants showing tospovirus-like symptoms of yellow mosaic, chlorosis, and necrosis were collected. Each leaf sample was tested by double-antibody sandwich (DAS)-ELISA using specific antisera (Bioreba, Reinach, Switzerland; Loewe, Sauerlach, Germany; DSMZ, Braunschweig, Germany) for the presence of the aforementioned tospoviruses. Based on the results, TYFRV were found in 21 samples (17.6%) collected from five fields surveyed. None of the samples had a positive reaction in ELISA to GRSV, INSV, IYSV, TCSV, TSWV, and WSMoV. To confirm testing, six leaf samples that were found positive for TYFRV in ELISA tests were mechanically inoculated on Petunia × hybrid and Nicotiana rustica; for all the samples studied, the inoculated plants showed typical necrotic local lesions of tospoviruses, and chlorotic or necrotic spots followed by systemic infection, respectively; their infection was subsequently confirmed by ELISA. Four out of the six samples also were tested by reverse transcription (RT)-PCR technique using previously described specific primers (2). The PCR reaction, in agreement with ELISA tests, resulted in the specifically amplification of a ~1.2-kb fragment of TYFRV RNAs. Using the PCR amplification primers mentioned above, the nucleotide sequences of nucleoprotein (N) genes of two isolates, namely TY-PepT43 and TY-PepT74, were determined (GenBank Accession Nos. KC354692 and KC354693, respectively); BLAST search results confirmed the presence of TYFRV and showed high nucleotide identities (99.0%) to TY-PF36 isolate of the virus. The virus has been previously reported on potato, tomato, ornamental plants, and some weed species in Tehran Province (1,3,4). This coupled with the presence of TYFRV vector, i.e., Thrips tabaci, in the same region (1), may have resulted in the occurrence of the virus on pepper plants. To our knowledge, this is the first report of the natural occurrence of TYFRV from pepper plants in Iran.
References: (1) T. Ghotbi et al. Plant Dis. 89:425, 2005. (2) A. R. Golnaraghi et al. Plant Dis. 92:1280, 2008. (3) R. Pourrahim et al. Plant Dis. 91:609, 2007. (4) S. Winter et al. Plant Pathol. 55:287, 2006.