Characterisation of Plum pox virus (PPV) isolates associated with Sharka infection in Northern and Southern Italy

Several PPV-infected stone fruit samples, collected in four Italian regions (Veneto, Lombardia [Lombardy], Campania and Basilicata), have been examined to obtain more information on biological, serological and molecular traits of PPV isolates. In particular, 36 leaf samples, collected from symptomatic plants, have been analysed by biological tests, TAS-ELISA, RT-PCR and RFLP. Total RNAs have been used in RT-PCR test, then the obtained amplicons were digested with AluI and RsaI restriction enzymes. DNA fragments respective to the replicase (NIb) and CP gene, have been cloned and sequenced. Molecular analysis confirmed the preliminary biological and serological data. All tested isolates belonged to PPV-M strain and 13 of them were very closely related to the PPV-SK68 isolate based on their coat protein sequence.