Applications and challenges of DNA barcoding in rapid radiation groups: (Crassulaceae) as a case study.

Objective: et (Hongjingtian in Chinese, RCRR), the roots and rhizomes of and its application in the medicinal market is very chaotic. In this study, DNA barcoding database and identification engine of species were established, decoction pieces from the medicinal market were identified, and the application and challenges of DNA barcoding in the rapid radiation of species were analyzed. This study provides reference for the protection, rational development, and utilization of endangered resources within species.

Methods: A total of 50 original plant samples from 20 species of the genus from Hebei, Xinjiang, Tibet, Jilin, and other major production areas were collected. Theses samples cover the typical distribution area (Qinghai-Tibetan Platea) of species and other scattered alpine regions (Changbai Mountain, Taibai Mountain, Lushan Mountain, etc.), it encompasses all species with thick rhizomes in China. ITS2 and barcode of database (BORD) were established and an identification engine named -IDE was developed. The stability and accuracy of the standard DNA barcoding database were evaluated using two datasets. -IDE identified 31 decoction pieces of from the medicinal material market.

Results: The BORD containing 1 532 sequences of 88 species has been established, and the identification efficiency results showed good accuracy and stability. According to the (2020 edition), 23 samples (74.2%) were identified as authentic , while the rest of the marketed varieties were , , and . The product label "Larger flower, Hongjingtian" was identified as . Samples labeled as "Smaller flower, Hongjingtian" were identified as , and .

Conclusion: ITS2 and barcodes can identify monophyletic groups represented by However, for non-monophyletic species, it is necessary to collect as many samples as possible and combine them with multiple markers for joint identification. This study discussed the application and challenges of DNA barcodes in under rapid radiation conditions, providing a scientific basis for the rational development and utilization of varieties.