He Shan, Xu Wei, Li Fei, Wang Yue, Liu Aizhong
Department of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Plant Divers. 2017 Jun 1;39(5):300-307. doi: 10.1016/j.pld.2017.05.007. eCollection 2017 Oct.
Investigation of the relationships of phenotypic and epigenetic variations might be a good way to dissect the genetic or molecular basis of phenotypic variation and plasticity in plants. Castor bean ( L.), an important non-edible oilseed crop, is a mono-species genus plant in the family Euphorbiaceae. Since it displays rich phenotypic variations with low genetic diversity, castor bean is a good model to investigate the molecular basis of phenotypic and epigenetic variations. Cytosine DNA methylation represents a major molecular mechanism of epigenetic occurrence. In this study, epigenetic diversity of sixty landrace accessions collected worldwide was investigated using the methylation-sensitive amplification polymorphism (MSAP) technique. Results showed that the epigenetic diversity (based on the polymorphism of DNA methylated loci) exhibited a medium variation ( = 1.395, = 0.242, = 0.366) at the population level though the variation was great, ranging from 3.80% to 34.31% among accessions. Both population structure analysis and the phylogenetic construction (using the neighbor-joining criteria) revealed that the two main clades were identified, but they did not display a distinct geographic structure. After inspecting the location of polymorphic methylated loci on genome we identified that the polymorphic methylated loci occur widely in nuclear and organelle genomes. This study provides new data to understand phenotypic and epigenetic variations in castor bean.
研究表型变异与表观遗传变异之间的关系，可能是剖析植物表型变异和可塑性的遗传或分子基础的一种好方法。蓖麻（Ricinus communis L.）是大戟科的一种单种属植物，是一种重要的非食用油籽作物。由于蓖麻表现出丰富的表型变异但遗传多样性较低，因此它是研究表型和表观遗传变异分子基础的良好模型。胞嘧啶DNA甲基化是表观遗传发生的主要分子机制。在本研究中，利用甲基化敏感扩增多态性（MSAP）技术对全球收集的60份地方品种材料的表观遗传多样性进行了研究。结果表明，表观遗传多样性（基于DNA甲基化位点的多态性）在群体水平上呈现中等变异（H = 1.395，I = 0.242，P = 0.366），尽管变异幅度很大，不同材料间的变异范围为3.80%至34.31%。群体结构分析和系统发育构建（采用邻接法标准）均表明，可识别出两个主要分支，但它们并未呈现出明显的地理结构。在检查了多态性甲基化位点在基因组上的位置后，我们发现多态性甲基化位点广泛存在于核基因组和细胞器基因组中。本研究为理解蓖麻的表型和表观遗传变异提供了新的数据。
