基于RNA-Seq SSR标记的沙棘种质遗传多样性和群体结构分析

Genetic Diversity and Population Structure Analysis of Sea Buckthorn Germplasm Based on RNA-Seq SSR Markers

沙棘是中国重要的生态经济植物,遗传多样性分析对于其种质资源的评价与保存十分重要。现以80个沙棘品种/品系为试材,利用17对多态性的RNA-Seq SSR引物,研究其遗传多样性和群体遗传结构。17对SSR引物共扩增出50条谱带,其中多态性谱带41条,每个位点条带数在2～5之间;多样性指数(PIC)介于0.150 7～0.588 6,平均0.271 0。利用PowerMarker 3.25和UPGMA方法进行聚类分析。结果显示,供试材料可分为两大类群,蒙古沙棘(ssp. mongolica)和杂交品种/品系聚为一个类群,中国沙棘(ssp. sinensis)构成另外一个类群。群体遗传结构分析中所有种质也被分成两个类群,杂交品种/品系介于中国沙棘和蒙古沙棘之间,与中国沙棘聚为一个类群。这些结果表明,沙棘的遗传多样性与它们的来源和遗传背景相符,可为沙棘种质资源保存和分子标记辅助育种提供理论依据。

Sea buckt horn is an ecologically and economically valuable species in China. The genetic diversity analysis of sea buckthorn is very important for the evaluation and conservation of its germplasm resources. In this study, 80 sea buckthorn cultivars/lines were used as materials and 17 pairs of polymorphic RNA-Seq SSR primers were used to analyze their genetic diversity and structure. Among 50 alleles generated by the 17 SSR loci, 41 were polymorphic alleles, and the number of bands ranged from 2 to 5 per locus. The value of polymorphism information content(PIC) varied from 0.150 7 to 0.588 6, with an average of 0.271 0. Cluster analysis based on unweighted pair group method with arithmetic average(UPGMA) using PowerMarker 3.25 divided all the genotypes into two main groups, with all of the ssp. mongolica cultivars and hybrids in one group and ssp. sinensis cultivars in the other group. 80 cultivars/lines were also divided into two populations by the population genetic structure analysis.Hybrids were between ssp. mongolica and ssp. sinensis cultivars and close to the latter. These results indicated the genetic diversity of sea buckthorn samples was in good agreement with their source and genetic background, which could provide theoretical reference for the conservation and molecular marker assisted breeding of sea buckthorn germplasm.