Figure 3.

Top: symptom expression in Gynura aurantiaca (A), Chrysanthemum morifolium (B) and Solanum lycopersicum (C) infected with natural variants (CEVd^COL, CEVd^E_117) and the corresponding mutated variants (CEVd^MCOL, CEVd^ME‐117) obtained by site‐directed mutagenesis. Bottom: viroid titres in plants infected with CEVd^COL, CEVd^E‐117, CEVd^MCOL and CEVd^ME‐117, as determined by Northern blot hybridization with a CEVd‐specific DNA probe. Ethidium bromide staining of a nondenaturing polyacrylamide gel shows that RNA levels (6S and 5S RNAs) in all preparations are comparable.