背景:茶树起源于中国西南部。贵州高原是茶树的原始中心,种质资源丰富。然而,遗传多样性,该地区栽培型茶树的种群结构和分布特征未知。在这项研究中,探讨了贵州高原栽培型茶树种的遗传多样性和地理分布。
结果:我们使用112,072高质量的基因分型测序分析遗传多样性,主要成分,系统发育,人口结构,和连锁不平衡,并开发了来自贵州高原的253种栽培型茶树种质。结果表明,珠江流域栽培型茶树种的遗传多样性明显高于长江流域栽培型茶树种。三个推断的纯组(CG-1,CG-2和CG-3)和一个推断的混合组(CG-4),通过人口结构分析确定,并通过主成分和系统发育分析进行了验证。确定了CG-2和CG-3的最高遗传距离和分化系数。分别确定了CG-4vsCG-2和CG-4vsCG-3的较低遗传距离和分化系数。我们开发了一个核心集和一个主要集。主要和核心集合包含初始集合中所有个体的77.0和33.6%,分别。主要集合可以作为全基因组关联研究中的主要群体,而核心集合可能在多个治疗设置研究中作为核心群体。
结论:本研究揭示了贵州高原栽培型茶树的遗传多样性和地理分布特征。在珠江流域和长江流域的古代地方品种之间,发现遗传多样性和进化方向存在显着差异。主要河流和古枢纽在很大程度上负责珠江流域和长江流域古地方品种之间的遗传交换以及古枢纽进化群的形成。遗传多样性,本研究阐明的种群结构和核心集合将有助于进一步的遗传研究,种质保护,和茶树的育种。
BACKGROUND: Tea plants originated in southwestern China. Guizhou Plateau is an original center of tea plants, and is rich in germplasm resources. However, the genetic diversity, population structure and distribution characteristics of cultivated-type tea plants in the region are unknown. In this study, we explored the genetic diversity and geographical distribution of cultivated-type tea accessions in Guizhou Plateau.
RESULTS: We used 112,072 high-quality genotyping-by-sequencing to analyze the genetic diversity, principal components, phylogeny, population structure, and linkage disequilibrium, and develop a core collection of 253 cultivated-type tea plant accessions from Guizhou Plateau. The results showed Genetic diversity of the cultivated-type tea accessions of the Pearl River Basin was significantly higher than that of the cultivated-type tea accessions of the Yangtze River Basin. Three inferred pure groups (CG-1, CG-2 and CG-3) and one inferred admixture group (CG-4), were identified by a population structure analysis, and verified by principal component and phylogenetic analyses. The highest genetic distance and differentiation coefficients were determined for CG-2 vs CG-3. The lower genetic distance and differentiation coefficients were determined for CG-4 vs CG-2 and CG-4 vs CG-3, respectively. We developed a core set and a primary set. The primary and core sets contained 77.0 and 33.6% of all individuals in the initial set, respectively. The primary set may serve as the primary population in genome-wide association studies, while the core collection may serve as the core population in multiple treatment setting studies.
CONCLUSIONS: The present study demonstrated the genetic diversity and geographical distribution characteristics of cultivated-type tea plants in Guizhou Plateau. Significant differences in genetic diversity and evolutionary direction were detected between the ancient landraces of the Pearl River Basin and the those of the Yangtze River Basin. Major rivers and ancient hubs were largely responsible for the genetic exchange between the Pearl River Basin and the Yangtze River Basin ancient landraces as well as the formation of the ancient hubs evolutionary group. Genetic diversity, population structure and core collection elucidated by this study will facilitate further genetic studies, germplasm protection, and breeding of tea plants.