SUMMARY

Hop stunt viroid (HSVd), genus Hostuviroid, family Pospiviroidae is a circular single-stranded RNA 294-303 nt in size, infecting a large number of woody hosts, such as grapevine, Citrus spp. and Prunus spp. In this study, we report the identification and molecular characteriza-tion of HSVd variants isolated in Turkey from different naturally infected Prunus sources, including apricot, plum and peach. We determined the nucleotide se-quences of eleven isolates and found five new sequence variants of 296 (3 variants) or 297 (2 variants) nt, com-parable in length to previously known HSVd isolates. Multiple alignments and phylogenetic analyses showed that one apricot isolate (HSVd.AP1) clustered with the recombinant P-H/cit3 group, whereas all the others (one apricot; HSVd.AP23, two plum; HSVd.PL49 and HSVd.PL278 and one peach, HSVd.PE73) clustered with the Hop group, confirming the molecular variabili-ty of HSVd isolates. The sequence variability seems to be more related to the geographical origin of the isolates than to their hosts