EVIDENCE FOR THE PHYSICAL INTEGRITY OF FLAVESCENCE DOREE PHYTOPLASMASPURIFIED BY IMMUNOAFFINITY FROM INFECTED PLANTS OR LEAFHOPPERS AND THE PLANT PATHOGENICITY OF PHYTOPLASMAS FROM LEAFHOPPERS

Phytoplasmas were extracted from flavescence doree-infected broadbean (Vicia Saba) using a vacuole isolation medium, and were immunoaffinity purified from infected leafhoppers. Purified phytoplasmas from both h ost sources were immunolabelled and observed under the electron micros cope. The infectivity of the purified phytoplasmas from leafhoppers wa s checked by injecting healthy leafhoppers which were then allowed to feed on healthy V. faba seedlings. The appearance of typical symptoms in these plants, and the positive results obtained in ELISA with extra cts of some of the injected leafhoppers and with symptomatic V. faba, indicated that the purified phytoplasmas had retained their infectivit y and had multiplied in the injected leafhoppers which had become infe ctive. These results support a previous report that phytoplasmas purif ied by immunoaffinity chromatography are well preserved.