Detection and serotyping of Mediterranean plum pox virus isolates by means of strain-specific monoclonal antibodies.

Plum pox virus (PPV) is a major threat to the expanding Mediterranean stone fruit industry. In order to control the plum pox disease it is of utmost importance to detect early PPV foci and to identify the PPV isolates involved. A survey was therefore carried out in Albania, Cyprus, Egypt, Greece, Italy and Turkey by a double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) with the following monoclonal antibodies (MAbs): 5B (universal), 4DG5 (PPV-D-specific), AL (PPV-M-specific), TUV and AC (PPV-C-specific), and EA24 (PPV-El Amar-specific). A hundred and seventy Mediterranean PPV isolates were tested for strain type. PPV-M was detected in Albania, Cyprus, Greece, Italy, and Turkey; PPV-D was detected in Albania and Italy, whereas samples with natural mixtures of both strains were found in a couple of orchards in Albania. Seven PPV isolates from apricots in two Egyptian localities were recognized only by MAb EA24. In conclusion, DAS-ELISA with a combination of the universal MAb5B and the MAbs specific to the four PPV serotypes currently known (M, D, C and El Amar) is an efficient tool for a simple, sensitive and routine detection of PPV and discrimination of its serotypes.