Conventional octaplex PCR for the simultaneous identification of eight mainstream closely related Dendrobium species

Abstract

As one of the most valuable medicinal genus in folk medicine and industrial crop, Dendrobium is cultivated extensively in south of China with distinct species. Pharmacological functions vary greatly among different Dendrobium species but their identification is somewhat difficult since they do not have unsophisticated method to distinguish the given species in an admixture. In the present study, an octaplex PCR assay was developed for rapid and reliable identification of eight mainstream, closely related Dendrobium species or their admixture consisting of D. devonianum, D. aphyllum, D. strongylanthum, D. officinale, D. nobile, D. chrysotoxum, D. huoshanense, and D. fimbriatum. The optimized multiplex PCR in this study utilized one specific primer derived from chloroplast trnL-F region and seven specific primer pairs from internal transcribed spacer sequences. Multiplex PCR yielded products of 148 bp, 210 bp, 265 bp, 340 bp, 397 bp, 448 bp, 491 bp, and 584 bp amplicons in the presence of D. fimbriatum, D. huoshanense, D. chrysotoxum, D. nobile, D. officinale, D. strongylanthum, D. aphyllum, and D. devonianum, respectively. The multiplex PCR approach was validated in 242 Dendrobium specimens from different production areas. As the results were species specific, the botanical origin of 20 samples of commercial Dendrobii caulis could be identified. These results show that the developed multiplex PCR assay provides a rapid and reliable approach for routine terminal market control of Dendrobii caulis.