Molecular authentication and phylogenetic relationship of Bidens pilosa and its relative species

Abstract

Objective: To construct the phylogenetic relationship of Bidens pilosa and its relative species, and to accurately identify B. pilosa and its relative species. Methods: Total genomic DNA was isolated from B. pilosa and its relative species. Nuclear DNA internal transcibed spacer (ITS) and chloroplast gene psbA-trnH sequences were amplified and sequenced. The Kimura 2-parameter (K2P) distances were calculated. Authentication analyses were performed using Nearest Distance, BLAST1, and Neighbor-joining (NJ) methods. Results: The NJ trees (ITS and psbA-trnH data) indicated that the different populations of B. pilosa form a monophyletic clade [Bootstrap (BS) = 79% and 87%]. B. pilosa and B. pilosa var. radiata formed one monophyletic clade, and B. biternata was sister to B. bipinnata (ITS and combined data: BS = 100%). B. tripartita, B. cernua, and B. frondosa formed one monophyletic clade (ITS and combined data: BS = 100%; psbA-trnH data: BS = 99%). The inter-specific genetic distances (ITS and psbA-trnH data) between B. pilosa and its relative species were (0.00794-0.12880) and (0.005 18-0.074 52) which were far higher than intra-specific genetic distances of B. pilosa (0-0.00159) and (0-0.00252). Conclusion: The closest relative of B. pilosa is B. pilosa var. radiata. B. tripartita is closely relative to B. cernua and B. frondosa. The sister relationship between B. biternata and B. bipinnata is corroborated. ITS and psbA-trnH are two efficient barcodes for the authentication of B. pilosa and its relative species.