Molecular Characterization of Odontoglossum Ringspot Virus (ORSV) in Java and Bali, Indonesia

Abstract

Orchids are one of the important ornamental plants that were cultivated in tropical countries, including in Indonesia. Virus infections has been important limiting factor in orchids cultivation because it could decrease the orchids quality. Odontoglossum ringspot virus (ORSV) is one of the most reported viruses infecting orchids, which spread widely in the world. During 2010-2011 surveys of viral diseases were conducted in Jawa and Bali, Indonesia. The orchids were found infected by virus, showed symptoms of mosaic, mottle, chlorotic, necrotic, streak, wilting leaf and ringspot on leaf surface. Detection with Reverse Transcription-Polymerase Chain Reaction (RT-PCR) showed that only 5 from 88 samples were infected by ORSV with total incidence of 5.7%. Three leaf samples of Phalaenopsis sp., were infected, then called ORSV BOC, ORSV KRB and ORSV TNBB isolates, respectively. The results obtained by amplification of DNA band with 474 bp in length as expression of Coat Protein (CP) gene. Phylogenetic analysis based on nucleotide sequences of CP gene showed that ORSV BOC have similarity to ORSV Germany, whereas, ORSV KRB and ORSV TNBB lead to speciation that possibly to be a new strain. This study was proved that ORSV have entered and spread widely by infected orchids in orchids landscape (nursery), semi-natural forests (botanical gardens) and natural forest (national park) in Java and Bali, Indonesia.