基于分子谱系地理学和群体遗传学的当归栽培起源研究

The wild germplasm resources of Angelica sinensis (Oliv. ) Diels has been found rarely distributed in China, which need be protected badly. However, there are several problems of seriously deterioration of strains such as confused germplasm, high incidence of mottle disease, early pumping stems often happen in the cultivated A. sinensis. The seed breeding work of A. sinensis is difficult and has been delayed. In view of the above problems, this research is based on the theories of chloroplast genome phylogeography and nuclear genome population genetics and the facts that we have already collected the samples from the wild Angelica sinensis (Oliv. ) Diels populations in Gansu province. The wild and main cultivated populations and relatives of A. sinensis will be studied by using cpDNA sequence and SSR markers, the genetic diversity and genetic structure of which will be analyzed by building the reticulate evolution tree with the relevant molecular biology software. The purpose of this research is to find the possible origin area and species of cultivated A. sinensis and provide a new idea for resolving the problem of germplasm degradation of cultivated A. sinensis. The results of this study may provide data supports for conservation and protection of the wild germplasm resources of A. sinensis and also provide scientific basis for the building of protection zone and sustainable utilization of the wild resource of A. sinensis in the future.

当归Angelica sinensis (Oliv.) Diels野生种质资源目前在我国分布稀少，亟待保护，而栽培当归种质混杂，麻口病发病率高、早期抽薹等品质退化现象严重，良种繁育工作滞后。针对以上问题，本研究应用叶绿体基因组分子谱系地理学和核基因组群体遗传学理论，在已采集到甘肃部分地区野生当归居群标本的基础上，以野生当归居群、主要生产区栽培当归居群和当归近缘种居群为研究对象，采用cpDNA序列分析及SSR分子标记技术，利用分子生物学软件构建其序列网状进化树并分析当归群体遗传多样性和群体遗传结构，以期阐明栽培当归的可能起源地和起源种，为解决栽培当归种质退化提供新的思路，为当归野生种质资源保存和保护提供数据支持，为将来建立野生当归资源保护区和当归资源的可持续利用提供科学依据。

当归Angelica sinensis (Oliv.) Diels野生种质资源目前在我国分布稀少，亟待保护，而栽培当归种质混杂，麻口病发病率高、早期抽薹等品质退化现象严重，良种繁育工作滞后。针对以上问题，本研究首先对全国当归资源分布进行系统调查，采集到珍贵的野生当归标本；其次，通过高通量测序技术开发出18对具有多态性的当归SSR引物，并应用SSR分子标记对野生当归居群、主要生产区栽培当归居群和当归近缘种居群的遗传多样性和遗传结构进行研究；同时，应用ISSR分子标记技术对甘肃省栽培和野生当归居群的遗传多样性进行分析比较。. 结果表明：采集的当归野生居群为原始野生居群，而不是栽培居群的逸生，而栽培居群并非起源于采集到的野生居群，且其来源单一；当归遗传多样性水平较低，且野生居群遗传多样性低于栽培居群，野生当归资源亟待保护；③当归野生居群与栽培居群之间产生了显著的遗传分化，且野生居群分化程度明显低于栽培居群；④栽培当归的遗传距离与地理距离无显著相关性，与野生居群结果相反，表明种子混杂可能减弱当归栽培居群之间的地理分化。. 以上研究为当归遗传多样性保护和建立野生当归资源保护区提供了理论依据；同时发现了不同于当归栽培居群基因型的当归野生居群基因库，为栽培居群基因型的改良及新品种的选育提供了优良的种质基因。