A Low Temperature Therapy and Meristem‐Tip Culture for Eliminating four Viroids from Infected Plants

Abstract

Viroid-free potato and chrysanthemum plants were obtained from meristem-tips cut from potato spindle tuber viroid-infected potato plants and from chrysanthemum plants infected with chrysanthemum stunt, chrysanthemum chlorotic mottle or cucumber pale fruit viroids after 6 months therapy in a growth chamber at 5 °C and 16 hours daily light of 5.000 lx intensity. Chrysanthemum plants survived quite well the conditions of therapy while potato plants grown from stem cuttings survived these conditions much worse and potato plants grown from tubers did not survive these conditions. PSTV-free plants were obtained from meristem-tips cut from sprouts grown from potato tubers infected with severe (s-PSTV) or mild (m-PSTV) strains of potato spindle tuber viroid after 6 months therapy at 6-7 °C in the dark. The tubers survived these conditions quite well.The 3 months therapy period was found too short for any plant material. The efficiency of 6 months therapy in viroid elimination varied for different viroids and different plant material from 18.5 to 80.0 %.

Elimination of chrysanthemum stunt viroid from an infected chrysanthemum cultivar by shoot regeneration from a leaf primordium-free shoot apical meristem dome attached to a root tip

“…Because these diseases are very difficult to eliminate from chrysanthemum plants by conventional apical meristem culture methods, much effort has been made to generate chrysanthemum plants completely free of CSVd. A long period of low-temperature treatment is effective in generating CSVd-free chrysanthemum plants (Hollings and Stone 1973;Paduch-Cichal and Kryczynski 1987). Alternatively, CSVd-free chrysanthemum plants can be generated from shoot tips cultured on a medium containing anti-virus agents (Horst and Cohen 1980).…”

Screening of Chrysanthemum Plants with Strong Resistance to Chrysanthemum Stunt Viroid

“…Elimination of viroids by traditional shoottip culture is therefore crucial. A long period of low temperature treatment (Hollings and Stone, 1973;Paduch-Cichal and Kryczynski, 1987) or the recently developed leaf primordia-free shoot apical meristem culture (Hosokawa et al, 2004a) enables the elimination of CSVd from infected plants. Application of in vitroculture of plants to all commercial cultivars is impractical, because culturing and maintaining in vitro plants is laborious and CSVd-free seedlings are quickly re-infected with CSVd in the field; therefore, plants resistant to CSVd are desirable.…”

Tomato chlorotic dwarf viroid in the ornamental plant Vinca minor and its transmission through tomato seed

“…Currently, there are >30 viroid species known and they are classified into two families, Pospiviroidae and Avsunviroidae (Flores et al 2005). Pospiviroids are considered to be hot-climate pathogens (Singh 1983) because they multiply at 25°C to 35°C (Sänger and Ramm 1975) and their generation is inhibited at lower temperatures (Lizàrraga et al 1980;Paduch-Cichal and Kryczynski 1987).…”