不同来源SSR和EST-SSR在披碱草属和鹅观草属物种中的通用性分析

The transferability of SSR and EST-SSR markers of different origins in Elymus and Roegneria in the Triticeae(Poaceae)

披碱草属和鹅观草属是禾本科小麦族两个重要的多年生属,其种属界限及系统关系一直存在争议,是其种质资源利用的难点.本研究基于小麦族中不同来源的已开发的SSR 标记,筛选出在披碱草属和鹅观草属中高通用性的SSR 标记,为其生物系统关系研究提供重要参考.试验选用了来自小麦族小麦、大麦、披碱草属、拟鹅观草属及赖草属5个属的230个SSR 和EST-SSR 标记对小麦族St、H、Y 基因组的23个物种进行了SSR 扩增及通用性分析.结果表明,1）在筛选的230个标记中,163个（70.87%）SSR 和EST-SSR 标记能在所有的供试物种中扩增出清晰的条带,在披碱草属和鹅观草属等物种中表现出了较高的通用性;2）在扩增出的163 个标记中,EST-SSR（87.60%）比基因组SSR（49.50%）标记在种属间表现出了较高的通用性,而基因组SSR 标记（85.98%）则比EST-SSR（79.37%）标记表现出更高的多态性;3）163个标记在供试物种中共扩增出579个清晰条带,其中多态性条带为533个,多态性比率为92.05%;每个标记扩增的条带数变化为1～11条,平均扩增条带数为3.55条;4）基于UPGMA 聚类结果与供试物种的基因组之间表现出了较高的相关性,相同或相似基因组物种间表现出较近的亲缘关系,其中H 基因组与St基因组的亲缘关系较远,H 基因组二倍体物种与其他物种也表现出了较远的亲缘关系.本研究选用的5个属的SSR 和EST-SSR 标记均能在披碱草属和鹅观草属物种中扩增,最后共筛选出了163个高通用性的SSR 和EST-SSR 分子标记,揭示了供试物种及不同基因组间的亲缘关系,为下一步披碱草属和鹅观草属的种属关系及系统学研究提供了重要参考.

Elymus and Roegneria,two important genera in the tribe Triticeae,include many important forage grasses,and also carry elite genes for improving cereal crops.However,there is ongoing dispute on the species boundaries and interspecific systematic relationships in the two genera.The biosystematic relationships in the group are of keen interest to agrostologists around the world.Based on known SSR markers in Triticeae,theobjective of this study was to screen out the high transferability markers for Elymus and Roegneria,which would provide important information for understanding the biosystematic relationships of the two genera.A to-tal of 230 simple sequence repeats (SSR)and SSR based on expressed sequence tags (EST -SSR)markers from 5 different genera including wheat,barley,Elymus ,Pseudoroegneria and Leymus ,were used to study the transferability to 23 species containing the St,H,and Y genomes.Among the 230 SSR markers,163 (70.87%)markers could generate clear bands,which showed a high transferability for those markers.The EST-SSR markers (87.60%)showed a higher transferability than genomic SSR markers (49.50%),but the genomic SSR markers showed a higher polymorphism (85.98%)than the EST-SSR markers (79.37%).A total of 579 bands were amplified from the 163 SSR markers able to generate clear bands,of which 533 bands were polymorphic.The number of amplified bands of each of these 163 SSR markers ranged from 1 to 11 with an average of 3.55 bands.Cluster analysis using the unweighted pair group method with arithmetic average (UPGMA)showed that the species with same or similar genome could be grouped together.Additionally,the H genome showed a rather distant phylogenetic relationship with St genome,and distant phylogenetic relation-ships were also revealed between the diploid species containing the H genome and other species in the study. The selected SSR markers from 5 genera could be amplified successfully in Elymus and Roegneria.To sum-marise,a total of 163 high transferability SSR markers were found to be suitable for the further phylogeny a-nalysis,which also revealed the phylogenetic relationships among the species.The results from this study pro-vide important information for improving understanding of biosystematic relationships between Elymus and Roegneria.