目的 構(gòu)建碎米椏Isodon rubescens及其與近緣種之間系統(tǒng)發(fā)育關(guān)系，準確鑒別碎米椏及其近緣種。方法 提取碎米椏及其近緣種DNA，對核基因ITS片段和葉綠體基因psbA-trnH序列擴增和測序，計算物種種內(nèi)、種間Kimura 2-parameter（K2P）遺傳距離。采用最近距離、相似性搜索、構(gòu)建Neighbor-joining（NJ）系統(tǒng)聚類樹3種方法進行鑒定分析。結(jié)果 ITS和psbA-trnH分子系統(tǒng)樹支持碎米椏5個居群樣本聚為一單系分支，支持率為94%和68%；其中，碎米椏與毛葉香茶菜、香茶菜和內(nèi)折香茶菜聚在一支，支持率為70%和51%；溪黃草和顯脈香茶菜構(gòu)成姐妹群分支，支持率為81%和63%。碎米椏及其近緣種種間ITS和psbA-trnH序列的K2P遺傳距離為0.007 08～0.072 61和0.008 06～0.024 76，均遠大于碎米椏種內(nèi)的遺傳距離0～0.001 76和0～0.002 68。結(jié)論 碎米椏與毛葉香茶菜、香茶菜和內(nèi)折香茶菜親緣關(guān)系較近，溪黃草和顯脈香茶菜親緣關(guān)系最近。ITS和psbA-trnH序列可以準確鑒別碎米椏及其近緣種。

Objective To construct the phylogenetic relationships of Isodon rubescens and its relative species, and accurately identify I. rubescens and its relative species. Methods Total genomic DNA was isolated from I. rubescens and its relative species. Nuclear DNA internally transcibed spacer (ITS) and chloroplast gene psbA-trnH sequences were amplified and sequenced. The Kimura 2-parameter (K2P) distances were calculated. Identification analyses were performed using Nearest Distance, BLAST1, and Neighbor-joining (NJ) methods. Results The NJ trees (ITS and psbA-trnH data) indicated that the five populations of I. rubescens formed a monophyletic clade [Bootstrap (BS) = 94% and 68%]. I. rubescens and I. japonicus, I. amethystoides, I. inflexus formed one monophyletic clade (BS = 70% and 51%), and I. serra was sister to I. nervosus (BS = 81% and 63%). The K2P genetic distances of ITS and psbA-trnH data between I. rubescens and its relative species were (0.007 08—0.072 61) and (0.008 06—0.024 76) which were far higher than intra-specific genetic distances of I. rubescens (0—0.001 76) and (0—0.002 68). Conclusion I. rubescens is closely relative to I. japonicus, I. amethystoides, and I. inflexus. The closest relative of I. serra is I. nervosus. ITS and psbA-trnH are two efficient barcodes for the identification of I. rubescens and its relative species.

國家自然科學(xué)基金面上項目（31070171，31270236）；科技部國家星火計劃項目（2012GA750004）