Existence of two serological subclusters of Plum pox virus, strain M

A large-scale serological characterisation of Plum pox virus (PPV) isolates was carried out with 19 monoclonal antibodies (MAbs), including the univer sal MAb5B and the following strain-specific MAbs: AL (specific to PPV-M), 4 DG5 (specific to PPV-D), TUV and AC (specific to PPV-C), and EA24 (specific to PPV-EA). The study involved 108 PPV isolates of different geographical origin (Albania, Bulgaria, Cyprus, Czech Republic, Egypt, France, Germany, Greece, Italy, Hungary, Moldova, Romania, Slovakia, Spain, Turkey and Yugos lavia) and hosts (almond, apricot, peach, plum and cherry). The inter- and intra-strain serological relationships of PPV isolates were evaluated by DA SI-ELISA. High serological variability was detected, not only between strai ns, but also among isolates of the same strain. Computer-assisted analysis of serological data support the hypothesis of the existence of two distinct subclusters, denoted PPV-M-1 and PPV-M-2, which seem to prevail in Mediter ranean and Eastern-Central European countries, respectively.