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چکیده
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Australian grapevine viroid (AGVd) is 369 nucleotide (nt) in length and was first described in Australia. AGVd has only been isolated from grapevines and does not appear to induce any symptom.In this study, grapevine leaves were collected from North- West Iran vineyards during summer 2010. Total nucleic acid (TNA) was extracted from leaves of 137 vines by the silica capture method and used as templates for reverse transcription (RT)-PCR using random hexamer primers. PCR fragments corresponding to full length AGVd were amplified for 130 samples by the use of specific primers. The RT-PCR products were purified from the agarose gel using the into the pGEM-T Easy vector (Promega) and used for transformation of competent Escherchia coli sequencer (MWG operon, Germany).The results showed that the Iranian variants were 367-369 nt. Also, these variants showed 94-100% homology between themselves, 93-96% with the reference sequence (NC-003553) and 82- 99% with other GenBank sequences at nucleic acid level. In total, nine new variants were identified. The Iranian isolates possessed unique secondary structures in comparison with the reference sequence (NC-003553). Sequences analyses showed various types of changes including transition, transversion, insertion, rearrangement and deletion occurring in pathogenesis region. Interestingly, we found changes in the lower and upper central conserved region (CCR) which has been reported only for CVD-III. Mutation in the lower strand of central domain but not in the CCR has previously been reported for other members of the genus Apscaviroid. AGVd is being reported for the first time from the northwest region of Iran.
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