Analysis of rDNA ITS Sequence of Wild Dendrobium Officinale
野生铁皮石斛rDNA ITS序列分析

This study was aimed to determine the sequence and analyze rDNA ITS sequences of samples of wild Dendrobium officinale from different origins. The feasibility of using ITS sequence to identify the origin of Dendrobium officinale was discussed. Total DNA was extracted and PCR was applied by using primer ITS5F/ITS4R. Then the PCR products are electrophoresised, purified, sequenced and submitted to GenBank. Clustal W was used to compare the multiple alignment of all 33 ITS sequences, including 11 submitted sequences in this article. Dendrobium nobile and Bulbophyllum odoratissimum were used as outgroup to analyze phylogeny by building neighbor-joining tree. The results showed that 11 sequences were selected to be submitted to the GenBank from all sequences. The achieved accession number was JF803235-JF803245. A total of 645 homologous sites, 9 informative sites (3 sites of ITS1, 4 sites of 5.8S, and 2 sites of ITS2) were obtained. Phylogenetic analysis showed that Dendrobium nobile and Bulbophyllum odoratissimum were in the base of the tree, and the other 32 Dendrobium officinale together were formed on large branches. No correspondence between the origin and the topology of phylogenetic tree were founded. It was concluded that due to the current lack of comprehensive standard of Dendrobium officinale samples and ITS reference sequence, only using ITS sequences cannot get enough phylogenetic information sites. Therefore, it is not feasible to speculate the origin of Dendrobium officinale.