蕙兰SSR引物开发及渝贵川地区兰属遗传多样性研究

采用磁珠富集法对野生蕙兰DNA进行SSR引物开发,并以开发出的多态性引物为研究工具,选取来自渝、贵、川3省(市)的9个野生兰属居群为研究对象,探讨遗传多样性与其地理位置分布的关系,从而在分子水平上为如何保护兰属植物提供有利参考。结果显示:8对SSR引物共扩增出53个等位基因,平均每个位点的等位基因为6.6250个,平均多态性位点百分率为98.6%。兰属植株个体间存在交配不平衡现象,Nei′s多样性指数范围为0.3158~0.8661,Shannon信息多样性指数变化范围为0.8833~1.3557。重庆黔江野生兰属居群的遗传多样性最高,79.97%的遗传分化存在于居群内,20.03%的遗传分化存在于居群间,居群内的变异高于居群间,基因流Nm<1,遗传漂变在兰属的遗传分化中起一定的作用。通过比较居群间遗传聚类结果与兰属植株采集地理位置的关系,发现野生兰花居群的划分在分子遗传学水平受其地理因素的影响较大。

Development of SSR Primers in Cymbidium faberi Rolfe and Study on Genetic Diversity of Cymbidium Sw.in Chongqing-Guizhou-Sichuan Region

SSR primers were developed by using the magnetic bead enrichment method in Cymbidium faberi Rolfe,and the polymorphic primers were used as research tools to explore the relationship between the genetic diversity and the geographical distribution for nine selected wild populations of Cymbidium Sw.from the Chongqing-Guizhou-Sichuan Region in China at the molecular level,it provides a useful reference for the protection of Cymbidium Sw.The results showed that a total of 53 alleles were amplified by 8 pairs of SSR primers.The average number of alleles per locus was 6.6250,and the average percentage of polymorphic bands(PPB)was 98.6%.Mating imbalance between individual plants of Cymbidium Sw.was detected.The range of Nei′s diversity index(N)was 0.3158-0.8661,and the range of Shannon information diversity index(I)was 0.8833-1.3557.The genetic diversity of the Qianjiang populations in Chongqing was the highest,with 79.97%of the genetic differentiation within the population,and 20.03%of the genetic differentiation between the populations,the variation within the population being higher than that between the local populations.The gene flow of Nm<1 indicated that the genetic drift played some role in the genetic differentiation of the Cymbidium Sw.By comparing the relationship between genetic clustering results among the populations and the geographic locations of the Cymbidium Sw.plants,it was found that the division of wild Cymbidium Sw.populations is greatly affected by geographic factors at the molecular genetic level.