DNA barcodes for delineating Clerodendrum species of North East India

The diversified genus of Clerodendrum with its complex evolutionary history leads to taxonomic mystification. Unlike traditional taxonomic methods, DNA barcoding could be a promising tool for the identification and conservation of Clerodendrum species. This study was attempted to develop an efficient barcode locus in Clerodendrum species of North East India. We evaluated four barcode candidates (ITS2, matK, rbcL, ycf1) and its combinations in different Clerodendrum species. The reliability of barcodes to distinguish the species were calculated using genetic pairwise distances, intra- and inter-specific diversity, barcode gap, and phylogenetic tree-based methods. The results exemplify that matK posse's maximum number of variables and parsimony-informative sites (103/100), intra- (0.021 ± 0.001) and inter- (0.086 ± 0.005) specific divergences and species resolution rate (89.1%) followed by ITS2, ycf1, and rbcL. Among the combinatorial locus, ITS2 + matK showed the best species discrimination with distinctive barcode gaps. Therefore, we tentatively suggest that the combination of ITS2 + matK as core barcode for Clerodendrum and converted into quick response (QR) code. Hence, this finding indicates that DNA barcoding could provide consistent resources for species discrimination and resolve taxonomic controversies of the genus as well as set a preliminary assessment toward its biodiversity.