基于ISSR数据探讨卷叶凤尾藓(Fissidens dubius P.Beauv.)遗传多样性

卷叶凤尾藓(Fissidens dubius P.Beauv.)是凤尾藓科凤尾藓属植物,该种分布广泛,形态变异强烈。为了解其遗传多样性及种群遗传结构特点,本研究利用ISSR分子标记对采集于浙江、福建、广西、四川、辽宁5个省区的卷叶凤尾藓14个自然种群的遗传多样性进行了评价。结果显示:筛选出的12对引物共扩增出259条清晰、重复性高的条带,其中多态性位点有248个,多态位点百分率为95.75%;种群总的Nei's基因多样性指数为0.2327,Shannon's信息指数为0.3701,说明卷叶凤尾藓遗传多样性水平较高;14个种群的遗传分化系数(Gst)为0.7078,种群间的基因流(Nm)为0.1864,表明大部分遗传变异(72.01%)存在于种群间,27.99%的遗传变异存在于种群内,即卷叶凤尾藓种群间遗传分化明显。基于ISSR数据的聚类分析表明,在遗传距离50为分组阈值处,14个种群可被分为6组(G1~G6):G1为来自于浙江省不同采集地点的8个种群(JHBS除外);G2由浙江金华北山种群(JHBS)组成;G3包括福建武夷山(WYS)和天宝岩种群(TBY);G4、G5、G6分别由广西龙胜县花坪种群(GX)、四川龙池种群(LC)、辽宁白石砬子保护区种群(BSLZ)组成,表明卷叶凤尾藓种群间的遗传分化主要由地理距离造成,种群内的遗传分化可能与其生境的异质性有关。

Genetic Diversity of Fissidens dubius P. Beauv. Based on ISSR Data

Fissidens dubius P. Beauv., a species of Fissidens Hedw. belonging to Fissidentaceae (Musci), is widely distributed and shows high morphological variation. To understand its genetic diversity and structure, 14 populations of F. dubius collected from Zhejiang, Fujian, Guangxi, Sichuan and Liaoning Provinces were tested using ISSR markers. Of the 56 ISSR primers tested, 12 were selected to amplify the DNA from 101 samples of the 14 populations, with 259 clear and repeatable bands obtained. We found 248 polymorphic loci, with 95.75% polymorphic loci, a Nei's genetic diversity index of 0.2327, and a Shannon's information index of 0.3701. The populations of F. dubius had a high level of genetic diversity. The genetic differentiation index (Gst) of the 14 populations was 0.7078, the gene flow among these populations was 0.1864, and the majority of genetic variation (72.01%) existed among populations, with only 27.99% existing within populations. These results demonstrated that F. dubius had obvious genetic differentiation among populations. Based on ISSR data, the dendrogram with a grouping threshold at a genetic distance of 50 showed that populations could be divided into six groups (G1-G6):Group 1 included eight populations from Zhejiang Province, except the Jinhuabeishan population, Group 2 included the Jinhuabeishan population, Group 3 included the Fujian populations from Wuyishan and Tianbaoyan, Group 4 included populations from Huaping of Guangxi Province, Group 5 included Longchi population of Sichuan Province, and Group 6 included Bashilazi of Liaoning Province. Our analyses showed geographical genetic differentiation among populations and genetic differentiation relative to habitat heterogeneity within populations of F. dubius.