Host ranges of Potato spindle tuber viroid, Tomato chlorotic dwarf viroid, Tomato apical stunt viroid, and Columnea latent viroid in horticultural plants

Host ranges of Potato spindle tuber viroid (PSTVd), Tomato chlorotic dwarf viroid (TCDVd), Tomato apical stunt viroid (TASVd), and Colmunea latent viroid (CLVd) were investigated in 30 species from 12 genera of horticultural plants that are frequently traded internationally. They were mechanically inoculated, and viroid infection was checked using both ways of reverse-transcription polymerase chain reaction and back-inoculation to tomato. Among 30 species examined, eight to 10 were susceptible to PSTVd, TCDVd, TASVd, and CLVd. Most of these species belong to the Compositae and Solanaceae families, and symptoms were only observed in Calendula officinalis, Petunia × hybrida, and Solanum melongena. These data indicate a risk of unexpected viroid expansion by international trading of vegetatively propagated asymptomatic plant materials.