Simultaneous detection of odontoglossum ringspot virus (ORSV) and cymbidium mosaic virus (CymMV) infecting orchids in Meghalaya, India by Multiplex RT-PCR

Abstract

• ORSV was found to be more prevalent than CymMV with the incidence percentages of 53.5% and 46.4% respectively. • Mixed infection of ORSV and CymMV was found to be 35.7%. • The Nucleotide sequences of ORSV and CymMV CP genes from Meghalaya showed high sequence identities of 96.90–99.56% and 96.91–99.66% respectively with other available sequences in Genbank. Odontoglossum ringspot virus (ORSV) and cymbidium mosaic virus (CymMV) are the most prevalent viruses infecting orchids all around the world. These viruses cause a serious threat to the orchid industry as they can spread from infected plants to healthy plants through vegetative propagation, contaminated tools, and human hands. This result in negative vigour of infected plants, showing stunted growth, producing fewer flowers, and decreasing flower quality. In this study, 84 leaf samples of orchids were collected from nine horti-hubs and orchid nurseries in Meghalaya. The orchid leaf samples were subjected to multiplex RT-PCR amplification using gene-specific primers targeting the coat protein (CP) genes of CymMV and ORSV. The most prevalent virus detected was ORSV with a 53.5% incidence while CymMV showed a 46.4% incidence. Mixed infections of ORSV and CymMV were detected in 30 samples (35.7%). The nucleotide sequences of ORSV and CymMV CP genes from Meghalaya showed high sequence identities of 96.90–99.56% and 96.91–99.66%, respectively when compared to other sequences in GenBank. The phylogenetic relationship among ORSV isolates and CymMV, based on infected host or geographical origin, showed no clear-cut clustering of isolates.