作 者 ：谢春花;李晓玲*;栾春艳;杨进;陈发菊;李争艳
期 刊 ：植物研究 2012年 32卷 (3)期 页码：311-319
关键词：中华蚊母树；SRAP；遗传多样性；遗传结构；保护策略；
Keywords:Distylium chinense, SRAP markers, genetic diversity, genetic structure, conservation strategy,
摘 要 ：利用SRAP分子标记技术，对湖北省河岸带植物中华蚊母树的4个自然居群和1个迁地居群的遗传多样性和遗传结构进行了分析。结果表明，中华蚊母树物种具有较高水平的遗传多样性，7对SRAP引物进行PCR扩增的多态性位点百分率（PPF）为80.43%，每个位点的等位基因数(A)为2，有效等位基因数(Ae)为1.34，总遗传多样性Nei’s基因多样性指数（Hp）为0.215 9，Shannon信息多样性指数(I)为0.350 9。在居群水平上，5个居群总的遗传变异Ht为0.218 8，居群内的遗传变异Hs为0.193 4，居群间的遗传分化系数Gst为0.116 1，表明在总的遗传变异中有88.39%变异存在于居群内，仅11.61%存在于居群间，居群间的基因流Nm为3.807 2，表明居群间有较大程度的基因交流。UPGMA聚类分析和主成分分析显示中华蚊母树主要分为两个居群组，在长江三峡沿岸香溪和乐天溪由于遗传距离比较近聚为一小类再与高家堰聚为一大类，而沿渡河和三峡植物园居群聚为另一大类，表明迁地居群三峡植物园的中华蚊母树与来自巴东沿渡河居群的样本亲缘关系最近，且三峡植物园迁地保护居群基本保育了其遗传多样性总水平。同时在分析讨论了中华蚊母树遗传多样性与其繁育系统、生境及其起源进化的关系的基础上，评价了中华蚊母树的保护策略，并在评价保护成果的基础上，提出了今后进一步保育的策略。结果还表明SRAP标记是分析中华蚊母树遗传多样性和遗传结构非常可靠的一种标记，而且这是使用SRAP标记研究中华蚊母树的首次报道。
Abstract:The genetic diversity and the genetic structure of four in situ populations and one ex situ conservation population of riparian plant Distylium chinense in Hubei province was investigated using sequence-related amplified polymorphism (SRAP) molecular marker technique. A high level of genetic diversity at the species level was observed with the selected 7 SRAP primer combinations generating 46 discernible DNA fragments, of which 37 (80.43%) were polymorphic. The observed number of alleles (A), the mean effective number of alleles (Ae), Nei’s gene diversity index (Hp) and Shannon’s information index (I) was 2.00, 1.34, 0.215 9 and 0.350 9, respectively. Within populations, the genetic variation was found to be mainly caused by the variation within populations, accounting for 88.39% of the total genetic variation and only 11.61% among the populations. The gene flow of D.chinense between populations was 3.807 2, which was a relative high gene flow and could efficiently prevent gene drift and maintain current genetic structure. Based on unweighted pair-group method with arithmetic averages (UPGMA) dendrogram and principal coordinates analysis (PCA) diagram, the five populations studied may be divided into two groups. Most accessions along riversides in Hubei province including Letianxi, Xiangxi and Gaojiayan populations were found in one group, which was further divided into two subgroups that corresponded to the their geographic distance. Yanduhe and Three Gorges Botanical Garden populations were clustered into another group, showing that the accessions of ex situ conservation population had relatively high relatedness with those from Yanduhe population. The mean genetic diversity in ex situ conservation population was higher than those in situ populations. Hence, the ex situ conservation program of Three Gorges Botanical Garden was considered to be successful in preserving genetic diversity of D.chinense. Moreover, combining the analysis of the genetic diversity with available information on breeding system, status of natural habitat and evolutionary history, we also evaluated the current ex situ conservation program and proposed some effective strategies to further conserve the species. The results also suggested that SRAP molecular marker technique is valuable and reliable for evaluation of the genetic diversity estimation in D.chinense and this is the first report on the application of SRAP molecular marker technique in D.chinense.