Molecular Diagnosis of Tomato Yellow Ring Virus (TYRV) on Alstroemeria in Khorasan Razavi Province, Iran

In October 2009, in one of the alstroemeria (Alatroemeria sp.) greenhouses, located in Khorasan Razavi province, tospovirus-like symptoms (necrosis) were observed on stems, petioles, flowers and leaves of some plants. Sap extracts from these plants were mechanically inoculated to indicator plants. Necrotic local lesions were observed on Petunia hybrida and Chenopodium quinoa. Necrotic local lesions followed by a systemic necrosis that caused the death of the plants were observed on Datura stramonium and Nicotiana benthamiana. On inoculated N. glutinosa plants, systemic necrotic spots were developed. Mechanical backinoculation on alstroemeria was failed. Leaves of symptomatic plants were tested for Tomato yellow ring virus (TYRV), Iris yellow spot virus (IYSV), Tomato spotted wilt virus (TSWV), Impatiens necrotic spot virus (INSV), Groundnut bud necrosis virus (GBNV), Groundnut ring spot virus (GRSV), Tomato chlorotic spot virus (TCSV) and Chrysanthemum stem necrosis virus (CSNV) with antisera specific to the viruses (raised against nucleocapsid protein) in double-antibody sandwich-ELISA. The reaction with antisera specific to TYRV was positive. Total RNA was extracted from the infected N. benthamiana plants for reverse transcription-PCR amplification with TYRV specific primers which amplified a fragment near 805bp band covering the nucleocapsid protein gene. This fragment was sequenced (Acc. No. HQ154130) and showed 99% amino acid sequence identity with TYRV from Fars (Acc. No. ABH07703), Tehran (Acc. No. AAV98587) and Markazi (Acc. No. ACT09488) provinces. To identify the virus strain, specific primers were used and TYRV-t strain was identified. Also the virus was transmitted from the infected D. stramonium plants to the healthy leaves of the host by Thrips tabaci. To our knowledge, this is the first report of natural infection of a monocotyledon plant by TYRV.