DNA BARCODING ANALYSIS OF RBCL, ITS, AND RPOC1 REGIONS FOR SPECIES IDENTIFICATION OF Stephania brachyandra Diels IN THAI NGUYEN PROVINCE

Abstract

Stephania brachyandra Diels is a valuable medicinal plant species belonging to the genus Stephania, which is currently facing serious threats due to overexploitation and habitat degradation. Accurate species identification is therefore essential for effective conservation and sustainable management of its genetic resources. This study aimed to develop and evaluate DNA barcoding markers for the identification of S. brachyandra collected from Thai Nguyen province, Northern Vietnam. Five samples were collected from five different districts and analyzed using three genetic regions, including rbcL, ITS, and rpoC1. Total genomic DNA was extracted using a modified CTAB method, followed by PCR amplification, sequencing, and comparative analysis with reference sequences available in the NCBI GenBank database. The results revealed high sequence similarity between the studied samples and S. brachyandra at both the rbcL and ITS regions. Notably, the rpoC1 region with a length of 465 bp was successfully characterized and deposited for the first time for S. brachyandra under the accession number OR389484, demonstrating clear discriminatory power from closely related Stephania species. The findings indicate that the combined analysis of multiple genetic regions with different evolutionary rates is an effective strategy for species authentication and phylogenetic studies. This study provides reliable molecular markers and a solid scientific basis to support the conservation and sustainable utilization of genetic resources of Stephania brachyandra in Vietnam.