龙胆属6种药用植物的 ITS 2序列分析

摘要

本试验采用ITS2序列进行龙胆属6种药用植物的亲缘关系分析。通过测定粗糙龙胆（Gentiana scabra）、三花龙胆（G ．tri-flora）和条叶龙胆（G ．manshurica）的ITS2序列，同时从GenBank下载包括滇龙胆（G ．rigescens ）、秦艽（G ．macrophylla）和麻花艽（G ．straminea）3种药用植物在内的27个样本ITS2序列，采用ClustalX、GeneDoc和MEGA 5.0软件比较分析龙胆属6种药用植物的ITS2序列特征，进而用MP、ML和NJ法分别构建了龙胆属植物的分子进化树。结果显示，龙胆属6种药用植物（包括粗糙龙胆、三花龙胆、条叶龙胆、滇龙胆、秦艽和麻花艽）的ITS2序列共有187个保守位点和39个变异位点，粗糙龙胆、三花龙胆、条叶龙胆、滇龙胆的 ITS2序列GC含量较高，分别为60.2％、60.6％、60.6％和60.0％；而秦艽和麻花艽的GC含量较低，分别为58.2％和56.3％。龙胆属6种药用植物中粗糙龙胆、三花龙胆和条叶龙胆3个物种间遗传距离较近，尤其是粗糙龙胆和条叶龙胆之间仅为0.005；滇龙胆和麻花艽间的遗传距离最远（0.117）。亲缘关系分析显示，龙胆草组物种（粗糙龙胆、三花龙胆和条叶龙胆）和秦艽组物种（秦艽、麻花艽）表现出更近的亲缘关系；滇龙胆和其他5种药用植物（粗糙龙胆、三花龙胆、条叶龙胆、滇龙胆、秦艽和麻花艽）间的亲缘关系则较远。ITS2序列可以作为进行龙胆属6种药用植物亲缘关系分析的依据。%To provide evidence for the molecular identification and phylogeny relationship analysis of six medicinal plants in Gentiana L .,three ITS2 sequence samples of three species in Gentiana L .were PCR amplified and sequenced ,and 27 samples from the GenBank were download-ed .Sequence features were compared and analyzed using ClustalX ,GeneDoc and MEGA 5.0 softwares ,and phylogenetic analyses were used to investigate their evolutionary relationships by neighbour -joining(NJ) ,maximum parsimony(MP) and maximum -likelihood(ML) .The results showed that there were 187 conserved sites and 39 variable sites in the ITS2 region of the six medicinal plants ;The G+C contents of ITS2 from G .scabra ,G .triflora ,G .manshurica ,G .rigescens were higher (60.2% ,60.6% ,60.6% ,and 60.0% ,respectively ) compared to those from G .macrophylla ,and G .straminea(58.2% and 56.3% ,respectively);among the six medicinal plants ,the genetic distances of three species between G .scabra ,G .triflora and G .manshurica were very small ,especially between G .scabra and G .manshurica ,which were only 0.005 , while the largest genetic distances between G .rigescens and G .straminea were 0.117;Medical plant species from section Pneumonanthe (G . scabra ,G .triflora ,G .manshurica) were proved to be closely related to that of section Cruciata(G .macrophylla ,G .straminea) ,and there was a distant relationship between G .rigescens and each of the other five medicinal plants in Gentiana L .based on phylogenetic analysis .The ITS2 sequence provides evidence for phylogeny relationship analysis of six medicinal plants in Gentiana L .