Immunodiagnosis of Prune dwarf virus using antiserum produced to its recombinant coat protein.

Certification represents the first line of defense against fruit tree viruses. For certification or surveys dealing with large number of samples, ELISA is still considered the technique of choice and requires a continuous supply of good quality antibodies. Prune dwarf virus (PDV) is among the major viruses affecting stone fruits; it belongs to the genus Ilarvirus named so for its isometric labile particles. Recombinant DNA technology was investigated for production of PDV antiserum to avoid labile virus purification and virus maintenance problems. The PDV coat protein gene (CP) was cloned into a protein expression bacterial plasmid vector which allowed a good level of expression of up to 2mg native protein/L culture. The recombinant PDV CP was injected into rabbits and the crude antiserum was successfully used in indirect ELISA at dilutions of up to 1:5000 to detect PDV in infected leaf samples. Similar results were obtained in dot blot immunoassays (DBIA). The antibodies were used in double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) and results were comparable to a reference commercial kit. The crude antiserum was efficiently used for coating ELISA plates, thereby reducing test costs.