Endangered Uyghur Medicinal Plant Ferula Identification through the Second Internal Transcribed Spacer

The medicinal plant Ferula has been widely used in Asian medicine, especially in Uyghur medicine in Xinjiang, China. Given that various substitutes and closely related species have similar morphological characteristics, Ferula is difficult to distinguish based on morphology alone, thereby causing confusion and threatening the safe use of Ferula. In this study, internal transcribed spacer 2 (ITS2) sequences were analyzed and assessed for the accurate identification of two salable Ferula species (Ferula sinkiangensis and Ferula fukangensis) and eight substitutes or closely related species. Results showed that the sequence length of ITS2 ranged from 451 bp to 45 bp, whereas guanine and cytosine contents (GC) were from 53.6% to 56.2%. A total of 77 variation sites were detected, including 63 base mutations and 14 insertion/deletion mutations. The ITS2 sequence correctly identified 100% of the samples at the species level using the basic local alignment search tool 1 and nearest-distance method. Furthermore, neighbor-joining tree successfully identified the genuine plants F. sinkiangensis and F. fukangensis from their succedaneum and closely related species. These results indicated that ITS2 sequence could be used as a valuable barcode to distinguish Uyghur medicine Ferula from counterfeits and closely related species. This study may broaden DNA barcoding application in the Uyghur medicinal plant field.