目的：评价以ITS2序列作为DNA条形码对峨眉山区桑科药用植物的鉴定作用。方法：于四川峨眉山地区采集桑科药用植物样本25个，提取DNA，对其ITS2序列进行PCR扩增并测序，从GenBank上下载23条同科ITS2序列；运用MEGA6.0对所有序列种间种内遗传距离进行计算分析，构建Neighbor Joining（NJ）系统进化树；利用TAXON DNA 软件分析所有序列种内、种间变异并作barcoding gap分析；从ITS2数据库中预测并比较样本ITS2序列的二级结构差异。结果：桑科样本种间K2P最小遗传距离（0.041）大于种内最大距离（0.005），并有较为明显的barcoding gap；NJ树显示种各属样本分别聚为一大枝，种内之间于各属分支中各聚为一支；各属及各种样品ITS2二级结构存在明显差异。结论：以ITS2序列作为DNA条形码，能够对桑植物进行准确、快速的识别和鉴定，准确地弄清物种之间的系统进化关系，为峨眉山区该属药用植物的分布、种群及种群量研究提供指导，对其质量控制、安全用药及资源保护及合理开发利用提供理论依据。

This study was aimed to evaluate the use of ITS2 sequences as DNA barcode to identify medicinal plants in Moraceae from E’mei area. Total genomic DNAs were extracted from 25 samples from different habitats. ITS2 sequences of these samples were amplified and bidirectional sequenced by PCR. The 23 samples were downloaded from the GenBank. Genetic distances were analyzed by MEGA 6.0. Identification analysis was presented intuitively by constructing neighbor-joining (NJ) tree, as well as differences in secondary structure of ITS2 sequences. Barcoding gap analysis was also conducted using TAXON DNA. The results showed that the minimum distance between species (0.041) was greater than the maximum distance within each species (0.005), with obvious barcoding gap. The NJ tree showed that four species differed obviously from each other, gathering in four different main branches. Same significant differences also appeared in secondary structures, which could be both used to separate them. It was concluded that ITS2 sequences can be used as DNA barcode to conduct accurate and rapid identification of Moraceae plants and clearly figure out the phylogenetic relationship among them, providing guidance to the distribution study of medicinal plants in this genus, as well as theoretical basis for quality control, medication safety and rational development of medicinal plants in Moraceae in E’mei area.

国家科技重大专项（2014ZX09304-307-001-019）：中药新药安全性检测技术与标准研究，负责人：谭睿；四川省中医药管理局项目（2016Z013）：四川常用藏药化学基因双指纹信息建设，负责人：任瑶瑶