Molecular and Biological Characterization of the Ir anian Isolate of the Australian Grapevine Viroid

Abstract

Australian grapevine viroid (AGVd), an apscaviroid of the family Pospiviroidae , was recently identified in vineyards of southern Iran. It had a relatively wide host range and caused stunting, leaf deformation, mottling and vei n clearing in experimental hosts upon mechanical inoculation of nucleic acid extracts or agroinfiltration of the viroid infectious cloned DNA. Predicted secondary structure of the AG VD-Ir showed a difference from the predicted structure of the type isolate in the viro id pathogenicity domain. Mutational analyses showed sequence changes introduced into th at domain of the AGVD-Ir clone decreased the viroid’s replication efficiency in planta but did not show any effects on its movement. Keywords: Grapevine viroids, Mutagenesis analysis, Host rang e, Replication efficiency, Viroid movement.