NATURALLY-OCCURRING VARIANTS OF CITRUS EXOCORTIS VIROID IN VEGETABLE CROPS

Four viroids were isolated in crops of tomato, eggplant, carrot and tu rnip. They were detected only after inoculation of 'Rutgers' tomato wi th nucleic acid extracts from field plants and were characterized as v ariants of citrus exocortis viroid (CEVd). The size of the variants ra nged from 371 to 374 nucleotides and they contained nucleotide exchang es and insertions affecting all structural domains. Symptoms were indu ced in tomato and carrot whereas eggplant and turnip responded as symp tomless carriers. As the samples came from an area where no citrus is grown, it appears that these viroids have a reproductive cycle indepen dent of this crop, and perhaps involving wild plants or other vegetabl es.