DETECTION AND VARIABILITY OF OLIVE LATENT VIRUS 3 IN THE MEDITERRANEAN REGION

RT-PCR and dot blot hybridization assays were successfully used for the detection of Olive latent. virus 3 (OLV-3): a newly discovered olive-infecting virus belonging to the family Tymoviridae. To assess the geographical distribution of OLV-3, a total of 224 olive samples were collected from eight Mediterranean countries and tested by RT-PCR and clot blot hybridization. According to RT-PCR assay, OLV-3 was detected in all surveyed Countries with in overall average infection of 30.4%, ranging from 17% (Portugal) to 56% (Turkey). In 12 of 68 samples (c 20%) shown to be infected by RTPCR, dot blot hybridization failed to detect the virus, Possibly because of the low concentration of target RNA Single strand conformation polymorphism (SSCP) analysis of the viral RNA dependent RNA polymerase (RdRp) domain, conducted oil the 68 FCR amplicons from infected trees of different geographical origin, yielded eleven heterogeneous patterns. Computer-assisted analysis of the RdRp nucleotide sequences showed that the level of variability among the isolates ranged from 5% to 17%. In a tree constructed with RdRp nucleotide sequences, viral isolates grouped into three distinct Clusters with no relation to their geographical origin. Even though preliminary, the results of the field Survey Indicate that OLV-3 ranks among the most widespread olive-infecting viruses in the Mediterrean basin.