Orchid fleck virus: an unclassified bipartite, negative-sense RNA plant virus.

Orchid fleck virus (OFV) causes chlorotic or necrotic spots in many orchid species. Its particle morphology and cytopathic effects are similar to those of nucleorhabdoviruses. Although OFV shares clear sequence similarities with rhabdoviruses, its taxonomic status is undetermined because its negative-sense RNA genome is bipartite. This review presents a general overview of classical and contemporary findings about etiology, serology, epidemiology, pathology, molecular biology, detection and prevention methods of orchid fleck virus. Because of the characteristics of OFV and viruses of the Rhabdoviridae and Mononegavirales, it is proposed that a new genus of negative-sense RNA plant viruses outside of the Mononegavirales be established with orchid fleck virus as the type species.