Molecular phylogeny of the endangered Vietnamese Paphiopedilum species based on the internal transcribed spacer of the nuclear ribosomal DNA

Abstract

We have sequenced the internal transcribed spacer (ITS) region (including ITS1, 5.8S, and ITS2) of 16 species and two varieties of the slipper orchid genus Paphiopedilum in Vietnam. The identification of relationship between those species was also assessed using molecular tool. Most of slipper orchid species in Vietnam are now endangered or threatened to extinction due high demand of ornamental trade of these beautiful species. However, it is difficult to distinguish them without their flowers. Therefore, it is needed to develop molecular markers to accurately identify these species. Our present study is in the view to set the first steps in constructing a molecular database of slipper orchids for future assessment of inter- and intra-specific molecular diversity of Paphiopedilum species from Vietnam, to contribute to the conservation of these valuable orchids. The results showed that highly variable areas (that contain many indels) in ITS region are useful for phylogenetic analysis as the dataset containing these long-indels areas and gave better Jack-knife supports in resolving the relationships of Paphiopedilum species than the modified dataset did.