APPLICATION OF DNA BARCODE ITS2 FOR IDENTIFYING Panax stipuleanatus Tsai et Feng IN TUYEN QUANG PROVINCE

Abstract

Panax stipuleanatus Tsai et Feng is a valuable medicinal plant naturally distributed in several mountainous regions of Northern Vietnam and is classified as a rare and endangered species due to overexploitation and habitat degradation. Accurate species identification is essential for effective conservation and sustainable use. In this study, the internal transcribed spacer 2 (ITS2) DNA barcode was employed to authenticate P. stipuleanatus using ten samples collected from natural populations in Tuyen Quang province (Tung Vai, Nam Dich and Nam Dan). Total genomic DNA was extracted from young leaf tissues using the CTAB method. The ITS2 region was amplified by polymerase chain reaction (PCR) using the primer pair ITS2-F/ITS4-R, sequenced and compared with reference sequences retrieved from the GenBank database. Phylogenetic relationships were inferred using the Neighbor-Joining method implemented in MEGA11 software. The ITS2 region was successfully amplified in all samples, yielding fragments of approximately 480 bp. Sequence similarity analysis revealed more than 99% identity with reference sequences of P. stipuleanatus (GenBank accession numbers MK408811.1, MK408807.1, and MK408781.1). Phylogenetic analysis showed that all samples clustered clearly within the P. stipuleanatus clade, with very low genetic distances (0.00 - 0.003) and were clearly distinct from other Panax species, including P. vietnamensis, P. ginseng and P. quinquefolius. These findings demonstrate that ITS2 is a reliable and effective DNA barcode for accurate identification of P. stipuleanatus, providing important support for taxonomic studies, germplasm authentication and conservation of this endangered medicinal plant in Vietnam.