用nrDNA ITS序列探讨小麦族含StH基因组物种的系统发育

Phylogeny of species with the StH genome in Triticeae(Poaceae) inferred from nuclear rDNA ITS sequences

小麦族中具StH基因组的物种被包含在广义披碱草属中。本研究利用nrDNA ITS序列,采用最大简约法、最大似然法和基于MJ算法的网状结构分析,对16个不同地理分布和形态特征的具StH基因组组成的物种及8个含St和H基因组的拟鹅观草属和大麦属的二倍体物种进行了系统发育分析。结果表明,1)过去归属于裂颖草属和猬草属的物种大松鼠尾巴草、瓶刷草和猬草与披碱草属物种关系较近,应当划入披碱草属中;2)北美的StH基因组物种聚类在一起,其亲缘关系较近,它们与欧亚大陆的StH基因组物种存在较大变异和分化;3)具StH基因组物种较大程度的变异和分化与物种的地理分布有关;4)St基因组和H基因组的二倍体物种分别存在较大的分化。同时本研究还讨论了造成小麦族StH基因组物种变异和分化的可能原因。

Species with the StH genome in Triticeae are included in the genus Elymus sensu lato.In order to investigate the phylogeny of the StH genome in Triticeae,nuclear ribosomal internal transcribed spacer（ITS） sequences of 16 species with the StH genome were analyzed together with those of five Pseudoroegneria（St） and three Hordeum（H） accessions.The maximum marsimony（MP）,maximum likelihood（ML） and median joining algorithm（MJ） methods were used to reconstruct the phylogenetic tree.The results indicated that：1） Sitanion jubatum,Sitanion hystrix and Hystrix patula are closely related to Elymus species,and should be transferred to Elymus;2） the StH genome species distributed in North American have close relationships.There is diversity and differentiation between the North American and Eurasian StH genome species;3） a certain degree of diversity and differentiation of StH genome species is in good agreement with their geographical distributions;4） a certain degree of differentiation was found in diploid species with St and H genomes.Meanwhile,the possible reasons for the differentiation of StH genome species are also discussed.