基于ITS2序列及其二级结构的市售前胡药材分子鉴定OA

Objective:To identify the species of commercial Peucedani Radix products based on the internal transcribed spacer 2(ITS2)sequence and its secondary structure.Methods:A total of 103 samples labelled as Peucedani Radix were collected from 11 producing regions distributed across five herbal markets in Anhui,Hebei,Guangxi and other provinces.Genomic DNA was extracted,and the ITS2 region was amplified by polymerase chain reaction(PCR)and bidirectionally sequenced.MEGA 6.0 was used for sequence alignment,and the guanine+cytosine(GC)content and genetic distances were calculated.A neighbour-joining(NJ)phylogenetic tree was constructed.The ITS2 secondary structure was predicted using the ITS2 database.Species identification was then performed.Results:Authentic Peucedani Radix and its adulterants formed separate clades in the NJ tree.The ITS2 secondary structures differed in both the size and number of stem-loops within the helical regions.Based on the NJ tree and secondary structure analysis,the commercial samples originated from seven distinct species:Peucedanum praeruptorum,P.terebinthaceum,Ligusticum brachylobum Franch.,P.harry-smithii var.subglabrum,Angelica sinensis,Glehnia littoralis,and P.medicum.Conclusion:The DNA barcode based on ITS2 combined with its secondary structure signature can reliably distinguish authentic Peucedani Radix from its adulterants.