ITS AND RBCL DNA BARCODING FOR MOLECULAR AUTHENTICATION OF THYMUS LINEARIS (LAMIACEAE) FROM THE KASHMIR HIMALAYA: A FIRST REPORT

Abstract

Background: DNA barcoding is an important molecular method for identifying species, particularly in taxonomically complicated genera like Thymus (Lamiaceae), where physical similarities might lead to misidentification. Molecular markers such as the chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit(rbcL) gene and the nuclear Internal Transcribed Spacer (ITS) region are commonly used in authentication and phylogenetic research. The current study aims to authenticate Thymus linearis from the Kashmir Himalaya using rbcL and ITS DNA barcodes and to establish reference sequences for future taxonomic and phylogenetic studies. Methods and Results: This study used an integrated taxonomic and DNA barcoding approach to authenticate Thymus linearis from the Kashmir Himalaya. Morphological identification was confirmed at the KASH Herbarium, while chloroplast rbcL and nuclear ITS regions were amplified and sequenced. Sequence similarity with authenticated GenBank records confirmed species identity. The ITS sequences generated represent the first publicly available barcode records for T. linearis. Neighbor-Joining phylogenetic analysis further validated the identification by clustering all accessions into a well-supported monophyletic clade. Conclusion: The study establishes the first ITS barcode references for Thymus linearis and was authenticated using rbcL sequences as well. These results support molecular authentication and offer useful genetic resources for future phylogenetic and taxonomic research in the genus Thymus.