Phylogeny of the genus Phalaenopsis (Orchidaceae) with emphasis on the subgenus Phalaenopsis based on the sequences of the internal transcribed spacers 1 and 2 of rDNA

摘要

Phytogenies of 17 species of the genus Phalaenopsis and two related species were derived based on sequence analysis of the internal transcribed spacer 1 and 2 (ITS1 + ITS2) of ribosomal DNA. A genetic distance matrix was determined based on sequencelength and base composition. Two phylogenetic trees were constructed following Maximum parsimony (MP) and the Neighbor-joining (NJ) methods. Seventeen Phalaenopsis species were shown to be a monophyletic group as supported by molecular data analysis from ITS1 and ITS2 sequences in this study. This result agreed that the genera Doritis and Kingidium could be treated as the genus Phalaenopsis. In addition, members of subgenus Phalaenopsis are not a monophyletic group. Within the subgenus Phalaenopsis, members of section Phalaenopsis are a monophyletic group. Both section Stauroglottis and Deliciosae are not monophyletic groups. Furthermore, members of the section Deliciosae and Esmeralda of subgenus Phalaenopsis are closer to subgenera Parishianae, Proboscidioides and Aphyllae and separated from the other Phalaenopsis species. In conclusion, this study supports the systematics of the genus Phalaenopsis at the generic level but not at the subgeneric level.