Use of chloroplast DNA barcodes to identify Osmunda japonica and its adulterants

Abstract

Osmunda japonica Thunb., a medicinal plant newly recorded in the Chinese pharmacopoeia, has been used for centuries for treatment of viral influenza, dysentery, and bleeding. Although O. japonica and its adulterants have different medicinal effects and clinical applications, it is difficult to differentiate O. japonica from its adulterants used in medicine. To distinguish O. japonica from its adulterants, two chloroplast barcodes (psbA-trnH and rbcL) were tested for the first time. Genetic distance, genetic divergence, maximum likelihood tree, barcoding gap, and identification efficiency were calculated and analyzed for identification of O. japonica and its adulterants. The results showed the two barcodes could be used to identify O. japonica and its adulterants, and the performance of psbA-trnH was better in terms of amplification, sequencing, genetic divergence, and variation. The psbA-trnH region resulted in less overlap than rbcL, and greater interspecific divergence. On the basis of psbA-trnH sequences, a pair of primers was designed for specific identification of O. japonica. Our findings indicated that psbA-trnH was the optimum barcode, and rbcL could be as a complementary barcode for authenticating O. japonica and its adulterants, which was helpful for further clinical application of the materials.