S25 - Session P2 - In vitro thermotherapy combined with chemotherapy-based methods for Cnidium officinale Makino virus elimination

Authors: Jiah Kim *, Yeong Jeong

Cnidium officinale is used for traditional medicinal plants and accounts for more than 10% of the herbal medicine market in Korea. The C. officinale do not produce seeds, so proliferation takes place as tuberous roots. However, commercially cultivated C. officinale , cucumber mosaic virus (CMV), apple stem grooving virus (ASGV) are common pathogens that can significantly reduce tuberous root yield and quality. We used C. officinale , a cultivar widely grown in Korea, infected with CMV and ASGV. We carried out the effectiveness of chemotherapy with different concentrations of ribavirin, thermotherapy at different temperatures, and combinations of these two methods on virus elimination. In this procedure, infected explants were regenerated on MS medium containing ribavirin at concentrations of 10, 20, and 40 mg/l for 4-week, followed by a thermotherapy treatment for 15 days at 25 ~ 37 °C. The survival and regeneration of plants were evaluated, and the efficiency of virus eradication was determined by reverse- transcription polymerase chain reaction with two primer pairs for each virus. Ribavirin treatments at 40mg/L of CMV and ASGV resulted in virus elimination rates of 89.5% and 94.7%, respectively, although the survival rate was rapidly decreased. The average regeneration of virus elimination plants after high-temperature treatments (33~37 °C) for 15 days decreased to less than 20%. The virus elimination efficiency of CMV and ASGV was enhanced by combining 20 mg/L ribavirin and thermotherapy at 33 °C resulting in high virus eradication efficiency (100% and 96%) better than single treatments. The results demonstrated that it was combined treatments were highly effective for eliminating CMV and ASGV.