In vitro elimination of cymbidium mosaic virus (CymMV) and odontoglossum ringspot virus (ORSV) from Cymbidium orchid

Abstract

Cymbidium orchids, esteemed for their enchanting beauty and delicate allure, are widely cultivated in Meghalaya and other north-eastern states of India. However, the prevalence of viral infections in Cymbidium orchid cultivation in the region has caused considerable concern among growers. Cymbidium orchids are mostly susceptible to cymbidium mosaic virus (CymMV) and odontoglossum ringspot virus (ORSV). Therefore, the primary approach to managing viral diseases in orchids involves eliminating virus-infected stocks and producing virus-free stocks. The present study evaluates the effectiveness of meristem culture, thermotherapy, and chemotherapy on the production of virus-free plants from the in vitro culture of Cymbidium elegans Lindl. (infected with both CymMV and ORSV) and Cymbidium Bremo (infected with CymMV). To confirm infection status, multiplex reverse transcription-polymerase chain reaction (mRT-PCR) was performed on 6-month-old in vitro plants before treatments and then on treated plants grown in vitro for 8 months after meristem culture, 4 months after thermotherapy, and 4 months after chemotherapy. Meristem culture achieved a 22.5 % virus elimination rate for both C. elegans and C. Bremo, whereas thermotherapy yielded a 37.5 % success rate in generating virus-free plants, and chemotherapy achieved an even higher rate of 55.0 % virus-free plants. Of the three in vitro therapies used in this study, chemotherapy was the most effective in producing virus-free orchid plants compared to thermotherapy and meristem culture.