SEQUENCE VARIABILITY OF HOP STUNT VIROID ISOLATES FROM STONE FRUITS IN TURKEY
M. Gazel, C. Ulubas Serce, K. Caglayan, F. Faggioli
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 characterization of HSVd variants isolated in Turkey from different naturally infected Prunus sources, including apricot, plum and peach. We determined the nucleotide sequences of eleven isolates and found five new sequence variants of 296 (3 variants) or 297 (2 variants) nt, comparable 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 variability of HSVd isolates. The sequence variability seems to be more related to the geographical origin of the isolates than to their hosts.