Genetic Analysis of the Bletillae Rhizoma and Its Common Adulterants Using Internal Transcribed Spacer 2 Molecular Barcoding

Aim: This study was designed to discriminate Bletillae Rhizoma from its common adulterants: Iris tectorum, Polygonatum odoratum and Polygonatum cyrtonema using molecular barcoding.

Place and Duration of Study: Department of Traditional Chinese Medicine, College of Pharmaceutical science, Soochow University, China, between February, 2015 and December, 2015.

Methods: Total genomic DNA was isolated from the leaves of Bletilla striata and similar species. The internal transcribed spacer 2 (ITS2) of the ribosomal DNA was sequenced after PCR amplification. A neighbor-joining (NJ) phylogenetic tree was constructed from the ITS2 sequences, using the software MEGA 6.0.

Results: The lengths of the ITS2 sequences of Bletilla striata, Iris tectorum and Polygonatum odoratum were 259 bp, 268 bp and 227 bp, respectively. The secondary structure of the ITS2 from Bletilla striata was obviously different in terms of the number, size and angle. The samples were clustered into three classes, and the NJ tree and systematic classification of the plants were consistent.

Conclusion: ITS2 could be used to identify the Bletillae Rhizoma and adulterants rapidly, and promote standardized planting.