基于MSAP技术对不同蒙古黄芪居群表观遗传多样性的研究

Epigenetic diversity of different populations of Astragalus membranaceus var. mongholicus based on MSAP technique

关键词:  蒙古黄芪, DNA甲基化,甲基化敏感扩增多态性, 表观遗传多样性, 表观遗传结构

Key words:  Astragalus membranaceus var. mongholicus, DNA methylation, methylation sensitive amplified polymorphism, epigenetic diversity, epigenetic structure

摘要:

为探讨不同蒙古黄芪居群的表观遗传特征,该研究利用甲基化敏感扩增多态性(methylation sensitive amplified polymorphism,MSAP)技术,分析了来自内蒙古武川、陕西子洲、山西浑源等8个居群259份蒙古黄芪样本的DNA甲基化水平和模式,并结合居群表观遗传多样性、居群表观遗传结构和NJ(neighbor-joining)聚类分析进行深入研究。结果表明:(1)筛选出的10对选择性扩增引物甲基化敏感多态性位点百分比在50%～79%之间,具有良好的多态性。(2)蒙古黄芪总甲基化平均水平(62.64%)大于非甲基化(37.36%),全甲基化平均水平(33.39%)大于半甲基化(29.25%),并且以全甲基化模式为主,同时在野生居群中总甲基化平均水平(58.97%)低于栽培居群(64.84%)。(3)蒙古黄芪居群表观遗传多样性水平(I:0.555 5±0.121 0)高于遗传多样性(I:0.209 7±0.102 1),其中野生居群表观遗传多样性水平(0.553 1±0.114 8)略低于栽培居群(0.556 9±0.124 7),而遗传多样性水平(0.211 7±0.054 0)高于栽培居群(0.208 5±0.113 9); 分子方差分析显示表观遗传变异主要发生在居群内(79%)。(4)居群表观遗传结构和NJ聚类分析均将8个居群蒙古黄芪分为4组,各居群优先以地理进行聚类,表现出一定的表观遗传相似性。该研究结果共同揭示了蒙古黄芪群体表观遗传特征,为深入了解蒙古黄芪在不同环境条件下的表型变异与适应性策略提供了新思路,同时为制定合理的蒙古黄芪资源保护策略和开展优良性状的选育工作提供了表观遗传学视角。

Abstract:

To explore the epigenetic characteristics of different populations of Astragalus membranaceus var. mongholicus, a total of 259 A. membranaceus var. mongholicus samples from eight populations, including Wuchuan in Inner Mongolia, Zizhou in Shaanxi, Hunyuan in Shanxi et al., were analyzed for DNA methylation levels and patterns using methylation sensitive amplified polymorphism(MSAP)technology, combined with population epigenetic diversity, population epigenetic structure, and NJ(neighbor-joining)cluster analysis. The results were as follows:(1)Ten pairs of selective amplification primers were screened for good polymorphisms, with the percentage of methylation-sensitive polymorphic loci ranging from 50% to 79%.(2)The average level of total methylation(62.64%)in A. membranaceus var. mongholicus was greater than that of unmethylation 37.36%, the average level of full methylation(33.39%)was greater than that of hemi-methylation(29.25%), and the full methylation pattern was predominant. Simultaneously, the average level of total methylation was lower in the wild population(58.97%)than in the cultivated population(64.84%).(3)The level of epigenetic diversity(I: 0.555 5±0.121 0)was higher than that of genetic diversity(I: 0.209 7±0.102 1)in A. membranaceus var. mongholicus populations, where the level of epigenetic diversity in the wild population(0.553 1±0.114 8)was slightly lower than that of the cultivated population(0.556 9±0.124 7), and the level of genetic diversity(0.211 7±0.054 0)was higher than that of the cultivated population(0.208 5±0.113 9); AMOVA analysis showed that epigenetic variation mainly occurred within populations(79%).(4)Both the epigenetic structure of the populations and NJ cluster analysis divided the eight populations of A. membranaceus var. mongholicus into four groups, and the populations were preferentially clustered by geography, showing some epigenetic similarity. The research results on DNA methylation, population epigenetic diversity, population epigenetic structure, and NJ cluster analysis of A. membranaceus var. mongholicus reveal the epigenetic characteristics of A. membranaceus var. mongholicus population, providing a new idea for further understanding the phenotypic variation and adaptive strategies of A. membranaceus var. mongholicus under different environmental conditions. Simultaneously, this study provides an epigenetic perspective for formulating a reasonable resource protection strategy for A. membranaceus var. mongholicus and conducting the breeding of excellent traits.