有毒中药土荆皮的ITS2条形码序列分析鉴定

目的:本文选用土荆皮及其5种伪品共37份材料,对ITS2序列进行比较研究。方法:采用CodonCode Aligner3.5.7进行序列拼接,MEGA5.0计算土荆皮的种内及其与混伪品的种间K2P距离,构建NJ分子系统树,并分析土荆皮及其混伪品ITS2序列二级结构的分子形态学特征。结果:土荆皮药材ITS2序列单倍型与其基原植物叶片序列一致;土荆皮及其混伪品的ITS2序列种间遗传距离远大于土荆皮种内样本的遗传距离;NJ树显示土荆皮样品单独聚为一支,药材土荆皮正伪品的ITS2序列二级结构差异显著。结论:ITS2可以作为土荆皮及其伪品鉴定的有效DNA条形码序列。

ITS2 Sequences as Barcodes for Identifying and Analyzing Pseudolaricis Cortex

Pseudolaricis Cortex and its adulterants were identified using DNA barcoding technique in this study. The sequences of ITS2 of Pseudolaricis Cortex and its five adulterants including 37 samples were analyzed. Sequences were assembled using CodonCode Aligner 3.5.7. K2P distances were calculated and NJ tree was performed applying MEGA5.0. The ITS2 secondary structure was predicted using the ITS2 database and website. The results showed that the haplotypes of ITS2 regions of Pseudolaricis Cortex were the same as that of the original plant leaves. The inter-specific K2P distances of ITS2 were obviously higher than the intra-specific ones. Samples of Pseudolaricis Cortex were clustered into a single clade in the NJ tree. The secondary structure of ITS2 of Pseudolaricis Cortex was significantly different from its adulterants. Therefore, ITS2 could powerfully discriminate Pseudolaricis Cortex and its adulterants.