Identification of Eucommia ulmoides and its adulterants based on ITS2 sequences / 中草药

ABSTRACT

Objective: To identify Eucommia ulmoides and its adulterants using ITS2 barcode, to discuss the feasibility of this new method, and to provide the technical support for the prevention against the confusion of commercial medicinal materials. Methods: DNA was extracted from each sample as template, the ITS2 region was amplified by PCR technology and sequenced bidirectionally using DNA cloning sequencing method. The sequence assembly and consensus sequence generation were performed using the Seqman program. Phylogenetic study was performed by MEGA 4.1, and the Nighbor-joining (NJ) dendrogram was constructed. The ITS2 secondary structure was predicted using the ITS2 website. Results: The maximum Kimura-2-parameter (K2P) genetic distance of E. ulmoides was far lower than the minimum K2P genetic distance of the adulterants. In the cluster dendrogram, E. ulmoides samples from various sources showed the monophyletic and simultaneously distinguished from the adulterants. To compare the ITS2 secondary structure, it could be noticed that ITS2 secondary structure could distinguish E. ulmoides from its adulterants in terms of numbers, sizes, positions of loop, and the angles of helix exsertion in four helix regions. Conclusion: ITS2 barcode could be used to distinguish E. ulmoides from its adulterants effectively, and provide the important molecular evidence for the identification of germplasm rescouces and clinic safety in medicinal use.