基于matK序列的木犀属植物系统发育初步研究

Phylogenetic analysis of genus Osmanthus(Oleaceae) based on matK sequence

以流苏树属的流苏树,女贞属的女贞和木犀榄属的木犀榄作为外类群,利用叶绿体matK基因序列,对木犀属19个种进行种间亲缘关系及系统分类学研究。结果表明:①木犀属植物叶绿体matK基因序列较为保守,特别表现在3′端;②木犀属植物是一单系类群;③19种木犀属植物可以分为3个分支:香花木犀和华东木犀各单独聚为一个分支;其余聚为一个分支;其中美洲木犀、牛矢果和厚边木犀聚为一个亚分支,都属于圆锥花序组;木犀组的红柄木犀、毛木犀、石山桂、狭叶木犀和管花木犀组的山桂花5种植物聚为一个亚分支;其余的9种木犀组植物聚为一个亚分支;④经典的基于形态学的P.S.Green分类系统没有得到分子数据的支持,圆锥花序组聚在一起,而木犀组和管花木犀组之间的亲缘关系是交叉的。因此作者认为matK序列需要结合其他分子序列以及形态学指标进行综合分析,才能获得科学合理的木犀属分类系统。

Phylogenetic analysis of genus Osmanthus was performed based on sequence data of the chloroplast matK gene in 19 species and outgroups （Chionanthus retusus,Ligustrim lucidum and Olea europaea ）. The results showed that：1） sequence of the chloroplast matK gene in Osmanthus was more conservative,especially in 3＇ terminal; 2） the genus Osmanthus was a monophyletic group; 3） 19 species of Osmanthus were divided into three clades：O. suavis and O. cooperi constitute as a monophyletic clade; the others constitute as a clade：O. americanus,O. matsumuranus and O. marginatus constitute as a subclade,belonging to Sect. Leiole. Another subclade was constituted by O. armatus,O. venosus,O. fordii,O. attenuatus and O. delarayi; the other subclade was constituted by the remaining 9 species,belonging to Sect. Osmanthus; 4） the study result showed that the classical classification system of P. S. Green＇s based on morphology couldn＇t be supported by molecular data. Sect. Leiole constituted together,however,there was a cross-relationship between Sect. Osmanthus and Sect. Siphosmanthus. Therefore,we think that comprehensive analysis of matK sequence should be combined with other molecular sequences and morphological indicators in order to obtain scientific and reasonable classification of Osmanthus.