蒙古高原黄耆属部分争议种亲缘关系的ISSR分析

采用ISSR分子标记技术对蒙古高原黄耆属属下部分争议类群的亲缘关系进行了研究。用11条ISSR引物对8个种的45份材料进行扩增,共获得条带188条,其中多态性条带178条,多态性条带百分率达94.7%。用NTSYSpc2.10e软件对相关数据进行UPGMA聚类分析,在相似性系数为0.73处,45份材料被划分为7大类群,其中,科布尔黄耆(Astragalus koburensis)与乳白花黄耆(A.galactites)聚为一支,表明前者可能仅是后者的生态型,应当处理为后者的异名;不同产区的糙叶黄耆(A.scaberrimus)和变异黄耆(A.variabilis)分别聚为一支,其各自的形态变异得以区分,但均应属于种内变异的范畴;莲山黄耆(A.leansanicus)与长管萼黄耆(A.limprichtii)分别聚为一支,支持将二者处理为两个相互独立的种。在相似性系数为0.66处,45份材料又被划分为4大类,类群的划分与黄耆属属下"组"的划分接近,但又存有差别。PCoA分析的结果与UPGMA聚类分析基本一致。相关分析结果表明,以组为单位划分黄耆属植物具有合理性,但部分组的设立以及部分种的归属仍需调整,准确地揭示黄耆属植物间的系统进化关系,还需要更多的材料采用多种分子标记方法。

Genetic Relationships among Some Astragalus Species from Mongolian Plateau Based on ISSR Markers

Molecular characterizations of Astragalus L.species can elucidate the relationships among the species and provide more information about the taxonomy of this valuable genus.In this study,the genetic relationships among 45 Astragalus accessions from Mongolian Plateau and its surrounding areas were analyzed using inter-simple sequence repeat (ISSR) primers.11 selected ISSR primers generated a total of 188 valid loci,of which 178 exhibited polymorphisms.Unweighted pair-group method of cluster analysis based on dice similarity values separated the accessions into seven groups.Seven species were recognized within these groups.A.koburensis was placed in the same group as A.galactites accessions,showing that this species was only variants or ecotype of A.galactites.Pedicel variants of A.scaberrimus and pod variants of A.variabilis were also been detected by forming distinct subgroups within the clusters of these species.A.leansanicus was separated from A.limprichtii.The grouping of accessions was generally consistent with principal coordinate analysis (PCoA) and the results showed that it was reasonable to organize the species of Astragalus at section level,but some sections and the affiliation of some species should be modified.Application of multiple DNA marker systems and more samples from different species will help to reveal more accurately the phylogenetic relationships among Astragalus species.