Characterization of the sweet cherry isolate of plum pox potyvirus

An isolate of plum pox potyvirus from sweet cherry (PPV-SwC) in southern Italy was investigated. The isolate was mechanically or graft transmissible to different Prunus and Nicotiana spp. but not to Chenopodium spp. It was transmitted also by Aphis fabae and Myzus persicae in a nonpersistent manner. Restriction fragment length polymorphism analysis indicated and nucleotide sequencing confirmed that the isolate lacks AluI and RsaI sites in the C-terminal region of the coat protein (CP) gene. Western immunoblot results showed that the PPV-SwC CP has an electrophoretic mobility similar to that of strain PPV-D and faster than that of strain PPV-M. Double-antibody sandwich indirect enzyme-linked immunosorbent assay of the CP showed that PPV-SwC, although reacting with universal monoclonal antibodies to PPV, failed to react with antibodies specific to strains M and D. Results indicate that PPV-SwC is different from conventional strains of PPV but closely related to the sour cherry isolate of PPV from Moldova.