基于SNP标记的二倍体芋种质群体结构和遗传多样性分析

Population Structure and Genetic Diversity Analysis of Diploid Taro Based on SNP Markers

为评价国内外二倍体芋种质资源的群体结构和遗传多样性,本研究选取来自国内和东南亚的69份二倍体芋种质资源,利用扩增片段长度测序(specific-locus amplified fragment sequencing, SLAF-seq)技术开发SNP标记;基于这些高质量的SNP标记,进行了群体结构、系统进化树、主成分和遗传多样性分析。结果显示,经筛选共获得了27 121个高质量SNP标记;将69份芋种质分为5个群,与形态分类的结果一致。其中,野芋和匍匐茎魁芋的遗传关系较近,槟榔芋与花用芋遗传关系较近;野芋遗传多样性最高(Nei氏遗传多样性指数H=0.246,核苷酸多样性指数π=0.260),而槟榔芋的遗传多样性最低(H=0.127,π=0.118);5种形态类型的二倍体芋遗传分化明显(Fst=0.109~0.422),能够解释67.1%的遗传变异;而地理分布对芋种质资源的遗传变异贡献仅为18.5%。本研究为芋种质资源鉴定、保存和遗传育种提供理论基础。

In order to evaluate the population structure and genetic diversity of diploid taro germplasm resources,this study selected 69 diploid taro accessions from China and Southeast Asia to develop SNP markers using SLAF-seq(specific-locus amplified fragment sequencing);population structure,phylogenetic tree,principal components analysis,and the genetic diversity of 5 different morphotypes of taro had then been conducted.The results revealed that a total of 27121 high-quality SNP markers were obtained after filtering.Based on the developed SNPs,the 69 taro accessions were clustered into 5 groups,which were basically consistent with the morphological classification.Among the five morphotypes,there was a closer genetic relationship between wild taro and mono corm taro with rhizome,bun-long taro was closely related to multi-inflorescence taro.The wild taro had the highest(Nei's genetic diversity index H=0.246,nucleotide diversity TT=0.260),while the Bun-long taro showed the lowest(H=0.127,-0.118)on genetic diversity;the five morphotypes of diploid taro had significant genetic differentiation(Fst=0.109-~0.422),morphotypes accounted for 67.1%of the total genetic variation,while geographical distributions only contributed 18.5%to the total genetic differentiation of the 69 taro accessions.As a summary,this study provided a theoretical basis for the molecular identification,preservation and genetic breeding of taro germplasm resources.