Molecular Identification of Medicinal Dendrobium and Its Adulterants Based on DNA Barcoding

Purpose To screen the appropriate DNA barcoding and to establish a fast and accurate method for identifying medicinal Dendrobium.

MethodA total of 82 samples from 12 medicinal Dendrobium species were used as materials, after extracted the total DNA, ITS, ITS2, psbA-trnH and matK sequences were sequenced. Sequence characteristics, DNA barcoding gap and phylogenetic analysis were used by bioinformatics software.

ResultsThe amplification success rates of the four sequences were 100%. Among them, ITS and ITS2 had the highest sequencing success rate at 97.6%, then matK at 96.3%, and psbA-trnH at 95.1%; compared with other sequences, ITS and ITS2 sequences had fewer overlaps within and between species and had barcoding gap. The phylogeny showed that ITS and ITS2 sequences could successfully distinguish the 12 medicinal Dendrobium and its adulterants. The sequence of psbA-trnH failed to distinguish the three species, D. aurantiacum Rchb. f. var. denneanum, D. aurantiacum Rchb. f. var. zhaojuense and D. fimbriatum and their adulterants. The matK sequence failed to distinguish D. aurantiacum Rchb. f. var. denneanum and D. fimbriatum; the phylogenetic tree constructed by combining four sequences was similar to the phylogenetic tree constructed by ITS and ITS2 single sequence.

ConclusionThe DNA barcoding identification method based on ITS and ITS2 sequences and supplemented by psbA-trnH and matK sequences can quickly and accurately identify the medicinal Dendrobium and its adulterants.