基于叶绿体trnL-F序列对广义披碱草属物种的系统进化研究

摘要

The genus Elymus sensu lato includes Roegneria, Elymus, Hystrix, Sitanion, and Kengyilia. The plastid trnL-F sequence data were analyzed for their phylogenetic relationships, maternal donor, and for the origin and differentiation of St genomes by using Maximum Parsimony (MP) and Median Joining algorithm (MJ) methods. 1) The maternal donor of Elymus sensu lato was not always Pseudoroegneria. The P genome served as the maternal donor to Kengyilia melanthera and K. thoroldiana, while the Ns genome was the maternal donor for Hystrix duthiei and H. duthiei ssp. longearistata; 2) The MP tree revealed the close relationships between P, W and St genomes, while the H and Ns genomes were distinctly related to them; 3) K. melanthera and K. thoroldiana were clustered with diploid Agropyron species, which indicated the close relationships among them. H. patula was clustered in the St clade, while H. duthiei and H. duthiei ssp. longearistata were grouped in the Ns clade. The genomic constitution of H. patula was different from H. duthiei and H. duthiei ssp. longearistata; 4) The five diploid species with St genome did not form the monophyletic clades, suggesting the differentiation of the diploid species. The olyploid species with St genome were not clustered together, suggesting the differentiation of St genomes in polyploids; 5) The species distributed in Eurasia might originate from the diploid species of Pseudoroegneria from Asia, while the North American species might originate from North America Pseudoroegneria species. Some species might have a multiple origin and experienced recurrent hybridization between species with different genomes.%广义披碱草属包括了披碱草属、鹅观草属、猬草属、裂颖草属和仲彬草属.为深入研究这5个小麦族多年生属的系统地位、母本来源及St染色体组的来源和分化等问题,本研究根据叶绿体DNA trnL-F序列构建了系统树和网状结构图.结果表明,1)广义披碱草属物种的母本不完全来源于拟鹅观草属的St染色体组,其中黑药仲彬草和梭罗仲彬草的母本染色体组为P染色体组,Hystrixduthiei及长芒猬草的母本染色体组为Ns染色体组;2)系统树中反映了P、W和St染色体组之间具有较近的亲缘关系,它们与H和Ns染色体组的关系较远;3)仲彬草属中黑药仲彬草和梭罗仲彬草与冰草属的二倍体物种聚类在一起,表明黑药仲彬草和梭罗仲彬草与冰草属的关系较近;猬草属中猬草聚在St支中,而H.duthiei和长芒猬草包括在Ns支中,表明它们具有不同的染色体组组成;4)5个不同地理分布的具有St染色体组的拟鹅观草属二倍体物种没有形成一个单系组,表明St染色体组在二倍体物种中存在一定程度的分化;在异源多倍体物种中,其St染色体组的质体序列构成了不同的分支,表明St染色体组在多倍体物种中也具有分化;5)亚洲分布的拟鹅观草属二倍体物种可能参与了大部分欧亚物种的起源,北美分布物种的St染色体组可能来源于北美的拟鹅观草属物种;有些物种在多倍化起源过程中可能发生了重复杂交过程.