云杉矮槲寄生遗传多样性的ISSR分析

Genetic Diversity of Arceuthobium sichuanense Revealed by ISSR Markers

为探究云杉矮槲寄生(Arceuthobium sichuanense)的遗传多样性及其与不同寄主选择压力和地理分布的关系,采用ISSR分子标记方法,对青海、甘肃、四川等地区5种寄主上的100份云杉矮槲寄生样本进行遗传多样性和遗传结构分析。结果表明:(1)10条引物共扩增出130个条带,其中多态性条带129条,多态位点百分率(PPB)为99.23%。(2)物种水平上的Nei’s遗传多样性指数(He)和Shannon信息指数(I)分别为0.313 9和0.476 5,表明云杉矮槲寄生物种水平的遗传多样性较高,但群体间的基因流(Nm=0.528 7)较弱,可能会加速群体间的遗传分化(Gst=0.486)。(3)UPGMA聚类结果显示,来自甘肃、青海的样本聚为一组,表现出较高的相似性,而四川的样本独立聚类;不同寄主来源的聚类结果显示,寄生于鳞皮云杉(Picea asperata)与川西云杉(P.likiangensis var.balfouriana)的样本聚为一类,而寄生于青海云杉(P.crassifolia)、青杄(P.wilsonii)和紫果云杉(P.purpurea)的样本聚为一类,表明地理隔离和寄主选择压力对云杉矮槲寄生的遗传分化起到了重要作用。

Arceuthobium sichuanense belongs to semiparasitic seed plants.To explore the genetic diversity of A.sichuanense and its relationship with the host selection and geographic distribution,we collected100samples on5species of Picea from3sites which distributed in Sichuan,Gansu and Qinghai provinces,and molecular marker of A.sichuanense was conducted by ISSR technology.The results demonstrated that130bands were amplified by10primers,among which129bands were polymorphic,accounting for99.23%.Genetic diversity analysis showed Nei s genetic diversity(H e)was0.3139and Shannon s genetic information index(I)was0.4765,indicating that the genetic diversity among100samples was abundant.Gene flow among A.sichuanense populations was relatively weak(N m=0.5287),which might limited the genetic differentiation among the populations(G st=0.486).The unweighted pair-group method with arithmetic average(UPGMA)dendrogram classified the100strains into two major groups.The two groups could be further divided into3and2subgroups,respectively.Based on the different hosts,A.sichuanense grown on P.asperata and P.likiangensis var.balfouriana clustered into the first group,and the others clustered into the second group.The result indicated that geographical isolation and host selection played an important part in the genetic diversity of A.sichuanense.