基于ITS2序列的中药材桔梗种子DNA条形码鉴定

目的：桔梗为中国常用大宗药食兼用中药材，种植面积广，建立基于DNA 条形码技术的桔梗种子鉴定方法具有重要意义。方法：本研究共收集29份中药材桔梗基原植物和种子样品；利用体式显微镜、X射线影像工作站观察种子的形态特征及种子成熟度；优化DNA提取方法；基于中药材DNA条形码鉴定系统（http://www.tcmbarcode.cn）和《中国药典中药材DNA条形码标准序列》对种子物种进行鉴定。结果：不同群体来源或同一群体来源桔梗种子形态特征存在较大差异，识别困难；本实验可以实现单粒桔梗种子（约1mg）的DNA提取、PCR扩增和序列测定；5份样品同一群体内种子ITS2序列存在差异；中药材DNA条形码鉴定系统和《中国药典中药材DNA条形码标准序列》可以作为种子物种鉴定的依据。结论：DNA条形码分子鉴定法可以对中药材桔梗种子进行鉴定，同时为中药材种质资源鉴定提供了新方法，对中药材种子质量标准的建立提供依据。

Identification of Platycodonis Radix Seeds by Using ITS2 DNA Barcode

Platycodonis radix is one of the common used herbs,and is widely applied for both medicines and food.To establish a method for identifying the Platycodonis radix by using DNA barcoding is a very important target.In this study,29 specimens including leaves and seeds of Platycod onis radix had been collected from nine provinces.The morphological characters were surveyed with stereoscopic microscope and X-ray workstation.DNA was extracted from a single seed via optimizing the DNA extraction method.The species identification for each sample was carried out according to DNA barcode identification system(http://www.tcmabarcode.cn)and standard Platycodonis radix barcodes from the book,The Standard DNA Barcodes of Chinese Material Medica in Chinese Pharmacopoeia.The results showed that the morphological characters and grades of maturity remain presented some differences among specimens from different sources.This experiment can realize the DNA extraction,PCR amplification and sequence determination of a single Platycodonis radix seed(about 1mg).ITS2 sequences from five seed specimens lacked consistence.The Chinese material medica DNA barcode identification system and The Standard DNA Barcodes of Chinese Material Medica in Chinese Pharmacopoeia can be used as references for the seed identification.It was concluded that the seed of traditional Chinese materials can be identified through DNA barcoding method,which will contribute to the seed and seedling standar dization project of medicinal materials.