Naturally occurring variants of citrus exocortis viroid in vegetable crops

Four viroids were isolated in crops of tomato, eggplant, carrot and turnip. They were detected only after inoculation of 'Rutgers' tomato with nucleic acid extracts from field plants and were characterized as variants of citrus exocortis viroid (CEVd). The size of the variants ranged from 371 to 374 nucleotides and they contained nucleotide exchanges and insertions affecting all structural domains. Symptoms were induced in tomato and carrot whereas eggplant and turnip responded as symptomless carriers. As the samples came from an area where no citrus is grown, it appears that these viroids have a reproductive cycle independent of this crop, and perhaps involving wild plants or other vegetables.