巴戟天与常见混伪品的rDNA-ITS序列分析及其分子鉴定

目的比较巴戟天与常见混伪品之间的rDNA-ITS碱基序列的差异及其规律,同时为巴戟天及混伪品的指纹图谱鉴别提供分子标记。方法对巴戟天及其常见混伪品的rDNA-ITS进行了PCR扩增、测序,并运用CLUSTALX、MEGA软件对该区进行序列分析。结果测定了巴戟天及其混伪品的rDNA-ITS区序列,包括ITS1、5.8S和ITS2全长序列以及18S、26S部分序列。巴戟天与假巴戟天、羊角藤在ITS1和ITS2区的差异性分别为2.9%~5.8%和2.9%~4.2%,而与虎刺在ITS1和ITS2区的差异性则为21.2%和18.9%。根据ITS序列特征构建的系统树,混伪品假巴戟天与羊角藤首先聚类,然后与巴戟天聚在一起,而虎刺则单独聚为一支。结论rDNA-ITS序列可作为巴戟天与混伪品的一种较好的分子指纹图谱的标记方法。

Ribosomal DNA-ITS sequence analysis and molecular identification of Morinda officinalis and its counterfeit species

Objective To compare the rDNA-ITS differentiation and its regulation between Morinda (officinalis) and its counterfeit species, and provide DNA molecular markers for the fingerprint identification of them. Methods The rDNA-ITS regions of M. officinalis and its counterfeit species were amplified and sequenced, then analyzed by means of CLUSTRAL X and MEGA softwares. Results The internal transcribed spacers (ITS) including ITS1, 5.8S, ITS2, and partial 18S and 26S were determined. In DNA DIST analysis, the range of diversity among M. officinalis and M. shughuaeusis, M. umbellata was (2.9%-)5.8% and 2.9%-4.2% based on ITS1 and ITS2; the range of diversity between M. officinalis and Damnacanthus indicus was 21.2% and 18.9% based on ITS1 and ITS2. Phylogenetic tree based on ITS and 5.8S sequence data indicated the M. umbellata and M. shuanghuaensis were closely related then with M. officinalis, while D. indicus was monophyletic group. Conclusion The rDNA-ITS sequence is a better molecular marker for idertification of M. officinalis and its counterfeit species.