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چکیده
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Grapevine yellow speckle viroid 1 (GYSVd-1), Grapevine yellow speckle viroid 2 (GYSVd-2) and Grapevine fanleaf virus (GFLV) are world widespread. Grapevine yellow speckle viroids able to induce yellow speckle (YS) and the simultaneous infection with GFLV with leads to increased symptoms called vein banding (VB). The presence of YS and VB were surveyed in Kurdistan province during August to September 2015 and 36 grapevine leaf samples with YS, VB and non-symptomatic were collected and tested by multiplex RT-PCT. Results of multiplex RT-PCR showed that 22, 21 and 7 samples were infected GYSVd-1, GYSVd-2 and GFLV, respectively. All seven vines were infected by GFLV; they also were infected by at least GYSVd-2. Notably, 5 out 7 of the vines which infected by GFLV, GYSVd-1 and/or GYSVd-2, VB symptoms were observed (Fig. 1; A and B) suggesting that the presence of GFLV with grapevine viroids not sufficient to express the VB symptoms. Probably various other factors, including climate conditions (Salman et al., 2014), sequence variability of viroids (Polvika et al., 1996; Salman et al., 2014) and virus and/or viroids titer (Szychowski et al., 1995), are involved in their symptoms appearance. We also observed VB and YS symptoms in vines which infected only by GYSVd-2 (Fig. 1; C and D). The ability of GYSVd-2 to induce mild VB symptom by grapevine viroids has been already reported (Martelli et al., 2014). In conclusion, these data showed that vineyards in west of Iran were infected by VB and YS diseases. Also, our data show that in Iran grapevine yellow speckle viroids can become more damaging as they elicit VB in vines simultaneously infected by GFLV that is widespread and by GYSVd-1 and/or GYSVd-2.
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