Evaluating the Feasibility of Five Candidate DNA Barcoding Loci for Philippine Lasianthus Jack (Lasiantheae: Rubiaceae)

INTRODUCTION: The pantropical genus Lasianthus Jack is identified for high phenotypic plasticity making traditional taxonomic identification difficult. Having some members with important medicinal properties, a precise complimentary identification through DNA barcoding is needed for species delineation. MATERIALS AND METHODS: In this study, 12 samples representing six Philippine Lasianthus species were used to determine the most efficient barcoding loci among the cpDNA markers (matK, rbcL, rps16, and trnT-F) and nrDNA (ITS) based on the criteria of universality, discriminatory power, and resolution of species. RESULTS: The results revealed that ITS has the recommended primer universality, greatest interspecific divergences, and average resolution of species. Among the cpDNA markers, matK and rbcL are recommended but with minimal resolution of species. While trnT-F showed moderate interspecific variations and resolution of Lasianthus species, rps16 has the lowest interspecific divergence and resolution of species. CONCLUSION: Consequently, ITS is the potential ideal DNA barcode for Lasianthus species. SUMMARY: ITS, matK, and rps16 markers have the excellent amplification and sequence quality. ITS marker has the highest interspecific divergence with the maximum values, followed by matK, rbcL, trnT-F, and rps16, respectively. All markers except rps16 yielded average resolution to Lasianthus species. ITS marker is the most ideal locus in terms of excellent universality, high interspecific discriminatory ability, and average species resolution. [Image: see text] Abbreviations used: ITS: Internal Transcribe Spacer, matK: maturase K, rbcL: ribulose-1,5-biphospahte-carboxylase, rps16: ribosomal protein 16 small subunit gene.