基于ITS和trnL-F序列碱基差异的繁缕及其近缘种的亲缘关系分析

Analysis of interspecific relationship among Stellaria media and its related species based on ITS and trnL-F sequence differences

应用PCR产物直接测序法分析了繁缕〔Stellaria media（L.）Villars〕及其近缘种和鹅肠菜〔Myosoton aquaticum（L.）Moench〕的ITS和trnL-F序列的碱基差异,并以孩儿参〔Pseudostellaria heterophylla（Miq.）Pax〕为外类群构建N-J系统树,分析了这些种类的种间亲缘关系。结果表明,供试的繁缕属（Stellaria L.）种类及鹅肠菜的ITS和trnL-F序列长度分别为521-784和788-951 bp,各有变异位点77和59个,其中信息位点分别为18和11个,种间碱基差异百分率分别为6.5%和3.1%。ITS的碱基组成为A22.1%、T20.9%、G28.5%和C28.5%,G＋C含量57.0%;trnL-F的碱基组成为A 35.9%、T33.7%、G 15.7%和C 14.8%,G＋C含量30.5%。繁缕、雀舌草（S.alsine Grimm）和箐姑草（S.vestita Kurz）的ITS和trnL-F序列一致;鹅肠菜的ITS序列中有4个位点与前述种类不同,但trnL-F序列则相同;中国繁缕（S.chinensis Regel）的ITS和trnL-F序列与孩儿参较相似。在N-J系统树中,鹅肠菜与繁缕、雀舌草和箐姑草聚为一支,表明它们的亲缘关系相对较近,支持将鹅肠菜重新归入繁缕属的分类处理。研究结果显示,ITS和trnL-F序列分析均可用于繁缕及其近缘种的鉴别,且ITS是更为适宜的分子标记。

The trnL-F and ITS sequence differences of Stellaria media（L.） Villars and its related species as well as Myosoton aquaticum（L.） Moench were determined by PCR direct sequencing,and N-J tree was constructed using Pseudostellaria heterophylla（Miq.） Pax as an outgroup to analyze the interspecific relationship.The results show that the length of ITS and trnL-F is 521-784 and 788-951 bp,with 77 and 59 variable sites,18 and 11 information sites,respectively.And the percentage of base differences of ITS and trnL-F sequences among different species is 6.5% and 3.1%,respectively.The nucleotide composition of ITS is 22.1% A,20.9% T,28.5% G and 28.5% C,with the G＋C content of 57.0%.The nucleotide composition of trnL-F is 35.9% A,33.7% T,15.7% G and 14.8% C,with the G＋C content of 30.5%.S.media,S.alsine Grimm and S.vestita Kurz have the same ITS and trnL-F sequences.The ITS sequence of M.aquaticum is different in 4 sites with the above three species,while its trnL-F sequence is the same.The ITS and trnL-F sequences of S.chinensis Regel are similar to those of P.heterophylla.M.aquaticum,S.media,S.alsine and S.vestita cluster together in N-J phylogenetic tree,indicating a relatively close relationship,which supports the suggestion of putting M.aquaticum back into Stellaria L.It is concluded that ITS and trnL-F markers can be used in identification of S.media and its related species,and ITS is a better molecular marker.