目的 构建鬼针草Bidens pilosa及其与近缘种之间系统发育关系，准确鉴别鬼针草及其近缘种。方法 提取鬼针草及其近缘种DNA，对核基因ITS片段和叶绿体基因psbA-trnH序列扩增和测序，计算物种种内、种间Kimura 2-parameter （K2P）遗传距离。采用最近距离、相似性搜索、构建Neighbor-joining（NJ）系统聚类树3种方法进行鉴定分析。结果 ITS和psbA-trnH分子系统树支持鬼针草不同居群样本聚为一单系分支，支持率为79%和87%；其中，鬼针草与白花鬼针草构成一单系分支，金盏银盘与婆婆针构成姐妹群分支，上述两分支ITS和联合数据支持率均为100%；狼把草与柳叶鬼针草、大狼把草构成一单系分支（ITS和联合数据支持率为100%，psbA-trnH数据支持率为96%）。鬼针草及其近缘种种间ITS和psbA-trnH序列的遗传距离为0.007 94～0.128 80和0.005 18～0.074 52，均远大于鬼针草种内遗传距离0～0.001 59和0～0.002 52。结论 鬼针草与白花鬼针草亲缘关系最近，金盏银盘与婆婆针构成姐妹群关系，狼把草与柳叶鬼针草、大狼把草亲缘关系较近。ITS和psbA-trnH序列可以准确鉴别鬼针草及其近缘种。

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 (0.007 94－0.128 80) and (0.005 18－0.074 52) which were far higher than intra-specific genetic distances of B. pilosa (0－0.001 59) and (0－0.002 52). 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.

科技部国家星火计划项目（2012GA750004）；国家自然科学基金面上项目（31070171，31270236）