Identification of medicinal plant Schisandra chinensis using a potential DNA barcode ITS2

Schisandra chinensis (Turcz.) Baill. grows mainly in the northeast China and its mature fruits are famous traditional Chinese medicine recorded in “Chinese Pharmacopoeia”. As a traditional medicinal herb, S. chinensis has been used as an astringent curing dry cough, asthma, night sweats, nocturnal seminal emissions and chronic diarrhea [1,2]. Modern medical research had proved that S. chinensis contains multiple active components used to protect liver [3–5], prevent senility [6–9], restrain oxidation [10,11], improve human body immunity ability [12], regulate the central nervous system and so on [13,14]. Commonly S. chinensis and its adulterants are frequently found in the market together. Schisandra sphenanthera Rehd. et Wils. is important traditional Chinese medicine recorded in “Chinese Pharmacopoeia”, too, but its active components of the kinds and levels are clearly different from S. chinensis [15]. Conventional viewpoints are that the medicinal value of S. chinensis is better than S. sphenanthera. But the two medicines are often mistaken for each other [16]. The identification of the two species of Schisandra is difficult when based solely on morphological characteristics. Additionally, some limitations in traditional taxonomy prevent this technique from meeting the complicated demands of species recognition [17]. As such, a method for the simple and accurate authentication of Schisandra is indispensible. As yet some works had been done to differentiation or identification of Schisandra species using RAPD, ISSR, rbcL and ITS [18–20]. Recently, being part of ITS, ITS2 was relatively easy to be amplified using one pair of universal primers [21,22]. In addition, ITS2 had been found to provide taxonomic signature in systematic evolution [23,24]. The ITS2 region was also a promising potential molecular marker to be used for rapid taxonomic classification [21,22]. To our best knowledge, applying ITS2 region to identify plant materials from Schisandra with such a large sample size and geographic range had not been reported. And these studies were not found whether the ITS2 region could be used as a genomic marker to identify different Schisandra populations from different ecological environment and geographical distribution. In the current study, we utilized ITS2 as a DNA barcode to distinguish medicinal plants within the Schisandra genus and populations in order to ensure their safe, effective application in traditional using. Abstract