RT-PCR, GYSVd1 (DQ408542, FJ940920), GYSVd2 (FJ940922, FJ940921), AGVd (FJ940923) and HSVd (EU647233) were identified in vineyards of southern Iran (Fig1). AGVd and HSVd were also detected in inoculated cucumber seedlings either alone or in mixed infection. No samples were found infected with Citrus exocortis viroid in surveyed vineyards. GYSVd1 and GYSVd2 were either associated with yellow speckle or with no symptoms. Yellow speckle symptoms were more severe in mixed infection with grapevine fanleaf virus and symptoms changed to yellow vein banding (15). AGVd and HSVd were associated with no obvious symptoms in grapevine as reported earlier but induced stunting and leaf rugosity in cucumber (5, 12). GYSVds were identified in vineyards more often than other viroids and AGVd had lowest frequency (Fig2). Molecular analysis showed some differences between Iranian grapevine isolates and their non-Iranian counterparts. GYSVd1, GYSVd2, HSVd and AGVd had 89-93%, 97-99%, 94-99% and 90-98% homology with the sequences deposited in the GenBank, respectively. Based on whole genome alignment and symptom expression Iranian, isolates of GYSVd are grouped with type II sequences (16); however they had enough difference to be considered as a new type. More isolates must be sequenced to confirm these results. They also had similar structure in hairpin I formation as variant IX (1, 10). AGVd had two extra nucleotides in the genome located opposite to pathogenicity domain. They caused a difference in secondary structure of the viroid. Grapevine isolates of HSVd were not homogenous and at least 5 different variants were identified by SSCP or sequencing. All of these isolates were grouped in hop type group of HSVd besides other HSVd-g isolates (1, 6, 10).

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