基于核基因ITS及叶绿体psbA-trnH和trnS-trnG基因怀地黄栽培起源探讨

目的从野生型驯化为栽培品种角度分析地黄Rehmannia glutinosa的遗传多样性,探讨河南焦作地区怀地黄的栽培起源。方法对地黄野生自然居群,栽培品种及其近缘物种ITS、psb A-trn H和trn S-trn G序列进行扩增和测序,分析比较中药材地黄野生自然居群,栽培品种间各序列的单倍型类型和核苷酸多态性,构建Neighbor-Joining(NJ)分子系统发育树。结果单倍型分析结果显示,地黄野生居群单倍型类型数量(ITS 6个,psb A-trn H 8个,trn S-trn G 9个)明显高于怀地黄栽培品种单倍型类型数量(ITS 3个,psb A-trn H 2个,trn S-trn G 3个)。地黄野生居群的单倍型多样性和核苷酸多样性均远高于怀地黄栽培品种间,在3个基因联合系统树上,地黄野生居群和栽培品种所有样品与茄叶地黄聚在一支,支持率为90%;23个栽培品种(29个样本)与来自温县的10号地黄野生居群聚为一支,支持率为78%。结论地黄野生型驯化为栽培品种过程发生了明显的遗传瓶颈,导致现存怀地黄栽培品种遗传基础狭窄,遗传多样性降低。怀地黄栽培品种可能起源于河南温县区域的地黄野生群体。

Origin of cultivated Rehmannia glutinosa based on chloroplast gene psbA-trnH, trnS-trnG, and nuclear ITS sequences

Objective In order to understand the genetic diversity of cultivated and wild Rehmannia glutinosa, and to unravel the origin of cultivated R. glutinosa. Methods The sequences of nuclear gene ITS and chloroplast gene psbA-trnH, trnS-trnG in cultivar and wild population of R. glutinosa were amplified and sequenced. Haplotype (gene) diversity and nucleotide polymorphism of three genes from wild and cultivars of R. glutinosa were analyzed and compared in this study. Phylogenetic tree was constructed based on combined three genes using Bayesian inference (BI) methods. Results Analysis of sequences indicated that the number of haplotype (ITS, 6; psbA-trnH, 8; trnS-trnG, 9) in wild population of R. glutinosa was obviously higher than the number of Haplotype (ITS, 3; psbA-trnH, 3; trnS-trnG, 3) in cultivars of R. glutinosa. Haplotype diversity and nucleotide polymorphism of wild population of R. glutinosa were far higher than that of cultivars of R. glutinosa. The NJ tree (combined three genes data) indicated that all cultivated and wild population of R. glutinosa, and R. solanifolia form a monophyletic cladePosterior probability (PP)=90%]. Twenty-three cultivars of R.glutinosa (including 29 samples) were clustered with Wenxian wild populations (PP=78%). Conclusion The results implied very low genetic diversity existed in cultivars of R. glutinosa induced by the severe genetic bottleneck during the process of domestication of wild R. glutinosa, which resulted in the narrow genetic basis of the existing cultivars and decreased genetic diversity. Furthermore, it appeared that wild populations in Wenxian-Henan area were involved in the origin of cultivars of R. glutinosa.