Systematics Section / ASPT
Tsai, Chi-Chu , Chiang, Yu-Chung , Chou, Chang-Hung .
Molecular phylogeny of Phalaenopsis Blume (Orchidaceae) based on the plastid and nuclear DNA.
A previous study of nuclear ribosomal DNA, internal transcribed spacer (ITS) region, showed a molecular phylogeny of Phalaenopsis (Tsai et al. 2006). In this study, plastid DNA, including the intron of trnL, the intergenic spacer (IGS) of trnL-trnF, and the IGS of atpB-rbcL, were sequenced from 54 species, which represents most of the living species diversity in the genus Phalaenopsis (Orchidaceae). Based on plastid DNA data, the results provided support for the monophyly of the genus Phalaenopsis and concurred in that Doritis and Kingidium are synonymous with Phalaenopsis, as suggested by Christenson (2001). These results are also in agreement with ITS data from the previous study. Within the genus Phalaenopsis, subgenus Polychilos was monophyletic based on plastid DNA analysis, but not monophyletic in ITS analysis. The subgenus Phalaenopsis was not monophyletic, since sections Esmeralda and Deliciosae were separated from sections Phalaenopsis and Stauroglottis based on both plastid DNA and ITS data. Subgenera Aphyllae and Parishianae were not shown to be monophyletic based on both plastid DNA and ITS data. Furthermore, the monotypic species of subgenus Proboscidioides, P. lowii, formed a clade with the subgenus Aphyllae based on both plastid DNA and ITS data. In conclusion, molecular data supported the systematics of the genus Phalaenopsis on the generic level but not on most of the subgeneric or sectional levels for most groups as described by Christenson (2001). The main incongruent phylogenetic pattern between the plastid DNA and ITS trees is that the four-pollinia Phalaenopsis species did not form a clade based on plastid DNA data. The incongruence of the four-pollinia Phalaenopsis species between plastid DNA and ITS data may be caused by the inheritance of cpDNA from maternal species and homogenization of ITS of rDNA from both parental species.[c.e.:srb]
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1 - Kaohsiung District Agricultural Research and Extension Station, Crop Improvement Division, Pingtung, 900, Taiwan
2 - Pingtung University of Science and Technology, Department of Life Sciences, Depart. Life Science, NPUST,, No. 1, Hseuhfu Rd. Neipu, Pingtung, 912, Taiwan
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Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM