无患子天然居群遗传多样性研究

Genetic Diversity of Sapindus mukorossi Natural Populations in China Based on ISSR

[目的]通过我国无患子主要分布区的居群样本,研究无患子天然居群的遗传多样性和遗传结构。[方法]采用ISSR分子标记技术,利用12条ISSR引物分析18个天然居群的265株个体样本。[结果]表明无患子遗传多样性水平较高,物种和居群水平上的多态位点百分率(PPB)分别为95.37%和57.82%,Shannon’s信息指数(I)分别为0.256 9和0.199 8,Nei’s遗传多样性指数(H)分别为0.390 9和0.298 0。AMOVA分析表明,18个居群间出现一定程度的遗传分化,且遗传变异主要发生在居群内。UPGMA聚类和Mantel检验结果表明,18个天然居群可分为2大组群,且居群间的地理距离与遗传距离之间不存在显著相关性(r=0.066 7,P=0.541 7>0.05)。[结论]无患子以自交为主,其天然居群遗传多样性丰富,居群内的遗传多样性高于居群间。研究结果可为无患子育种策略的科学制定和种质资源的有效保护及利用提供理论依据。

[Objective]To reveal the genetic diversity and genetic structure in natural populations of Sapindus mukorossi. [Method]The genetic diversity and genetic structure of 265 S. mukorossi individuals sampled from 18 natural populations distributed in China were examined using fifteen inter-simple sequence repeat（ ISSR） markers primers. [Result]The percentages of polymorphic bands（ PPB） at the species and population level were 95. 37%and 57. 82%,respectively. The Shannon＇s indexes（ I） of phenotypic diversity at the species and population level were 0. 256 9 and 0. 199 8,respectively,and Nei＇s genetic diversities（ H） at the species and population level were 0. 390 9 and 0. 298 0,respectively. These results indicated that S. mukorossi contains relatively high levels of genetic diversity. There was genetic differentiation among the 18 populations to a certain level（ GST： 0. 233 7; FST：22. 22%; AMOVA genetic differentiation： 24. 74%）,and most of the genetic differentiation occurred within populations. The UPGMA clustering and Mantel test showed that there was no significant correlation between the geographical distance and genetic distance（ r = 0. 066 7,P = 0. 541 7 〉0. 05）. [Conclusion]S. mukorossi was givenpriority to selfing. Its natural populations had abundant genetic diversity. And the genetic diversity of S. mukorossi within populations was higher than that among populations. The present study could provide a reference for the conservation and utilization of S. mukorossi.