基于SSR分子标记的野生山胡椒(Lindera glauca)核心种质的构建

Construction of Core Germplasm of Wild Lindera glauca Based on SSR Molecular Marker

为深入发掘和筛选中国野生山胡椒种质资源,本研究利用18对SSR引物(5叶绿体SSR和13核SSR),以基本涵盖中国大陆自然分布区的22个自然群体共303份野生山胡椒种质为材料,进行SSR基因分型分析,并绘制出原始种质的亲缘关系图。结果表明,18对引物共检测到Na=88,Ne为1.18～3.76,He为0.14～0.74,Ho为0～0.58,I为0.30～1.52,以及PIC为0.13～0.70。STRUCTURE分析和UPGMA聚类的结果都显示出22个自然群体适合被划分为三个亚类群。利用等位基因最大化(M策略)和遗传距离最大化(SAGD)法分别至少要在25%(71份种质)、15%取样比例下(45份种质)构建的核心种质才能够在所有遗传多样性指标上代表原始种质的遗传多样性(t检验不显著),并符合核心种质构建的标准。结合核心种质构建工作的同类研究,确定SAGD法(15%取样比例)是较适宜于构建山胡椒核心种质的方法。基于nSSR标记,SAGD法15%比例下构建的核心种质在Na、Ne和I指标参数上的保留率分别达到了原始种质的93.24%、104.67%和100.85%;基于cpSSR标记,与之对应的保留率分别为85.14%、107.45%和108.82%。通过此法筛选出的45份核心种质材料能够一定程度地代表中国整个野生山胡椒种质资源的遗传多样性。研究结果可为其他对非作物型木本植物的核心种质构建,尤其是兼有无性与有性繁殖的物种提供参考。

In order to further explore and screen the germplasm resources of wild Lindera glauca in China, 18 pairs of SSR primers （5 chloroplast SSR and 13 nuclear SSR） were used in this study to analyze the SSR genotyping of 303 wild Lindera glauca germplasms from 22 natural populations that basically covered the natural distribution areas in China's Mainland and the genetic relationship diagram of original gerrnplasm was drawn. The results showed that 18 pairs of primers detected Na=88. Ne was 1.18-3.76 and He was 0.14-0.74. Ho was 0-0.58 and I was 0.30-1.52, as well as PIC was 0.13-0.70. The results of STRUCTURE analysis and UPGMA clustering showed that 22 natural populations were suitable for being divided into three subgroups. The core germplasm constructed by using allele maximization （M strategy） and genetic distance maximization （SAGD） methodsat least 25% （71 germplasm） and 15% （45 germplasm） sample rate, respectively could represent genetic diversity of the original germplasmon all genetic diversity indicators （t test was not significant）, and conformed to the standard of core germplasm construction. Compared with other similar research of core germplasm, the SAGD （15% sampling ratio） was a suitable method for constructing L. gIauca core germplasm. Based on nSSR markers, the retention rate of Na, Ne, and I index parameters of core germplasm constructed by 15% proportion of SAGD reached 93.24%, 104.67% and 100.85% of the original germplasm, respectively. Based on cpSSR markers, the corresponding retention rate were 85.14%, 107.45% and 108.82%, respectively. And the 45 core germplasm materials screened by this method could represent the genetic diversity of the whole wild L. glauca germplasm resources in China to a certain extent. The research results herein would provide references for other core germplasm construction of non-crop woody plants, especially for species that have both asexual and sexual reproduction.