基于SSR标记和单拷贝核基因的蔷薇属植物系统发生分析

Phylogenetic relationships of the genus Rosa based on SSR markers and single copy nuclear gene

【目的】通过深入分析中国产野生蔷薇属植物的遗传背景,为其品种演化、系统分类提供分子学依据,也为种间杂交亲本的选择提供一定的指导,从而为进一步开发我国丰富的野生蔷薇属植物资源提供理论基础。【方法】本研究以50份蔷薇属植物样本、42个种或品种为研究对象,运用SSR标记及单拷贝核基因GAPDH对其遗传多样性进行分析。利用MAC-PR理论预测不同倍性蔷薇属植物的SSR基因型。【结果】在29个SSR位点上共计检测出382个等位基因变异,多态性信息含量介于0. 413 9至0. 934 0之间,平均值为0. 798 9。计算Bruvo遗传距离并构建了邻接树,解决了SSR标记在不同倍性样本之间应用困难的问题。同时基于GAPDH基因序列片段构建了50个样本的贝叶斯树。基于SSR标记构建的系统发生树显示,50个样本聚成了6个分类群,月季组、桂味组样本聚类效果较好,而其他种类与现有分类系统差异较大。通过测序及克隆成功获得了所有样本的GAPDH基因序列片段,其中,比对后的序列长度为841 bp,变异位点数164个;基于GAPDH基因的聚类结果与现有的分类系统也有较大的差异。【结论】蔷薇属植物基于遗传关系的分类体系与现有的植物学分类系统有较大的差别。月季组、合柱组间遗传关系十分紧密;芹叶组、桂味组没有形成单系类群,这两组间可能存在着基因交流事件;小叶组中两个种没有很近的亲缘关系。

[Objective] This research provides some information for the controversy over some taxonomy and phylogenetic problems on Rosa species, and provides basis for the selection of parents of interspecific hybrids. This will provide a theoretical basis for further development of abundant wild rose resources in China. [Method] In this study, 50 samples with 42 species and varieties of genus Rosa were used to analyze genetic relationships and construct phylogenetic trees based on SSR markers and single copy nuclear gene (GAPDH). In order to predict the genotype of polyploidies, MAC-PR method was used. [Result] A total of 382 alleles were detected at 29 loci. The polymorphism information content ranged from 0.413 9 to 0.934 0 with an average value of 0.798 9. Then we calculated the Bruvo distance and constructed NJ tree (Neighbour-joining tree). The problem to apply SSR markers in polyploidies was solved in the above-mentioned territory. The phylogenetic tree based on GAPDH fragment was also constructed by Bayesian inference. The phylogenetic tree showed that 50 accessions could be clustered into 6 taxa. The traditional classification system of Chinenses and Synstylae is mostly supported by molecular data while others not. GAPDH sequence fragments from all accessions were successfully obtained after cloning and sequencing. The sequence length was 841 bp with 164 variable loci. The phylogenetic relationship based on GAPDH did not correspond to traditional classification system. [Conclusion] The result showed that the genus Rosa in its traditional infrageneric circumscription is not supported by molecular data. Sect. Chinenses and Sect. Synstylae are closed in genetic relationship. Sect. Pimpinellifoliae and Sect. Cinnamomeae are not monophyletic and a predicted gene flow exists between these sections. Two species in Sect. Microphyllae are not related based on molecular data.