Transmission of Tomato chlorotic dwarf viroid by tomato seeds
Tomato chlorotic dwarf viroid (Pospiviroid, TCDVd) has been detected in several ornamental plants (e.g. Brugmansia, Petunia) and in tomatoes (Lycopersicon esculentum) grown in commercial glasshouses in Manitoba (Canada), Arizona (US) and Japan (RS 2008/006, RS 2009/021). Although seed-transmission was not obtained during the initial description of the viroid, its presence in commercial glasshouses raised again the possibility of transmission through tomato seeds. Studies were carried out in Canada on a viroid strain initially isolated from Vinca minor (which is also reported as a new host of TCDVd) and they showed that TCDVd was seed-borne in tomato. The viroid could be detected in high percentages in tomato seeds and seedlings. Soaking infected tomato seeds in a low concentration of sodium hypochlorite did not eliminate the viroid. This strongly suggested that TCDVd is seed-transmitted but further studies with different strains are needed to confirm these preliminary results.
Singh RP, Dilworth AD (2009) Tomato chlorotic dwarf viroid in the ornamental plant Vinca minor and its transmission through tomato seeds. European Journal of Plant Pathology 123(1), 111-116.