Production of monoclonal antibodies against apple proliferation phytoplasma and their use in serological detection

Two monoclonal antibodies were obtained against the apple proliferation phytoplasma that provide easy, rapid, specific and sensitive serological detection. They reacted specifically by using ELISA and immunofluorescence techniques with apple proliferation-infected periwinkles and apple trees from different regions in northern Italy and Slovenia, but not with several other phytoplasma isolates. We did not observe any monoclonal antibody reaction even using phytoplasmas belonging to the same phylogenetic group such as European stone fruit yellows and pear decline. Two serological techniques, immunofluorescence and ELISA, were compared with DAPI staining and PCR. From July until leaf fall ELISA was as sensitive as PCR but was more rapid and convenient than PCR; immunofluorescence was useful for specific detection of apple proliferation phytoplasma on roots throughout the year. Serological techniques could be conveniently applied in the roots, stems and leaves of apple trees depending on specific phenological stages of the plants.