Identification of Dichroa febrifuga and its adulterants based on DNA barcoding technology

As a famous traditional Chinese medicine,Dichroa febrifuga Lour.,belonging to the genus Dichroa in the family Saxifragaceae,is used to treat malaria and eliminate phlegm.However,considerable substitution and adulteration of D.febrifuga has occurred in China due to the difficulty in identifying D.febrifuga from its adulterants by morphological methods alone.In this study,a total of 64 samples labeled as D.febrifuga or its adulterants,belonging to six species,were collected and identified by DNA barcoding technology.Two-dimensional DNA barcodes were used to construct an'Internet Plus'identification system,which benefits the cross-platform communication of DNA barcode information.Our results indicated that 20% of D.febrifuga samples were adulterants,with Mahonia bealei being predominant.In addition,the length of the ITS2 sequence of D.febrifuga was 230 bp.The intraspecific K2P genetic distance was 0-0.0253,whereas the interspecific K2P genetic distance was 0.152-0.748.A neighbor-joining tree showed that D.febrifuga differed markedly from its adulterants,which provides pivotal molecular evidence for resource identification and clinical security.The establishment of the'Internet Plus'two-dimensional DNA barcode system could provide a theoretical basis for the application of two-dimensional DNA barcodes in the trade and standardization of Chinese medicinal material.