Identification of herbal tea ingredient Plumeria rubra and its adulterants using DNA barcoding

Abstract

ITS2 sequence was used as a barcode to identify herbal tea ingredient Plumeria rubra and its adulterants. Genomic DNAs from forty eight samples were extracted, the ITS2 sequences were amplified and sequenced bi-direstionlly, and then assembled and obtained using CodonCode Aligner. The sequences were aligned using ClustalW, the genetic distances were computed by kimura 2-parameter (K2P) model and the Neighbor-joining (NJ) phylogenetic trees were constructed using MEGA5.0. Results showed that the length of ITS2 sequence of P. rubra were 244 bp. The intra-specific genetic distances (0-0. 016 6) were much smaller than inter-specific ones between P. rubra and its adulterants(0.320 8-0.650 4). The NJ tree indicated that P. rubra and its adulterants could be distinguished clearly. Therefore, Using ITS2 barcode can accurately andeffectively distinguish herbal tea ingredient P. rubra from its adulterants, which providesa new molecular method to identify P. rubra and ensure its safety in use.