Odontoglossum ringspot virus-Coat protein gene transformation into Dendrobium orchids

Susceptibility of orchids to virus infection is a major problem for orchid growers and exporters. There are 2 species of virus, Cymbidium Mosaic Virus (CyMV) and Odontoglossom ringspot virus (ORSV), which infect various orchid genera in Thailand. Until now, a suitable method to control virus is unavailable. Using genetic engineering method to improve orchid for virus resistant is a challenge tool. We have transferred the coat protein gene of ORSV (ORSV-CP) to protocorms-like body (Plbs) of Dendrobium orchids using particle bombardment method. The gold particles coated with pMNK1005 plasmid containing hygromycin phosphotransferase gene (hpt), and pO102 and pOH101 plasmid containing ORSV-CP gene were co-transferred into orchids. Potentially transformants selected were identified by active growth on MS medium supplemented with hygromycin for 4 months. Transgenic orchids were confirmed for the successful integration of ORSV-CP and hpt gene in the orchid genome by PCR technique. The results showed that half of transgenic orchids contain both transgenes. The obtained transgenic orchids are furthur evaluating for resistance to ORSV.