木麻黄属的DNA 条形码鉴定研究

为验证DNA条形码序列在物种鉴定方面及物种的系统发育方面的广适性,本研究以黎药植物木麻黄为研究对象,收集木麻黄及其近缘种和混伪品22份样本,采用4对引物(ITS,ITS2,trnH-psbA,rbcL)分别进行PCR扩增,产物进行双向测序。利用CodonCode Aligner软件进行序列的拼接,采用MEGA5.1进行数据的处理。结果表明,利用ITS/ITS2可以区分木麻黄与其近缘种以及混伪品,样品的psbA-trnH,rbcL和ITS/ITS2 4个序列中,ITS/ITS2序列具有明显的DNA gap。基于ITS/ITS2序列构建的NJ树结果表明,木麻黄属所有样品聚为一类,呈现明显的单系性,与其亲缘关系较近的是藤黄科。因此,ITS/ITS2序列可以准确鉴定黎药的基原植物。并能从分子水平揭示木麻黄的系统演化规律。

DNA Barcoding the Plant of the Casuarina

In this research, Casuarina eguisetifolia Linn was used to verify the broadly suitability of DNA barcodes in identification of Li-medicine plants and systematic development of species. The genomic DNA of 22 samples collected C. eguisetifolia and its adulterants were amplified by 4 pairs of primers respectively (ITS (internal transcribed spacer), ITS2 (internal transcribed spacer 2), trnH -psbA , rbcL) and sequenced bi-directionally. Obtained sequences were assembled using CodonCode Aligner. The dates were analysised using MEGA5.1 in accordance with the kimura 2-parameter (K2P) model. The neighbor-joining (NJ) phylogenetic trees were constructed. Our study demonstrated the efficacy of ITS/ITS2 to distinguish between C. eguisetifolia and other adulterants species at the molecular level. Comparative to the primer of trnH -psbA and rbcL, there was a obviously DNA gap. The NJ trees showed that the several species of Casuarina can be classified to same types to show a obviously monophyly, which the nearest family was Guttiferae. Therefore, ITS/ITS2 regions can accurately distinguish the original plant of Li-medicine. The systematic evolution of Casuarina can be verified in the molecular level.