长柄石杉不同地理居群叶绿体DNA trnL-trnF序列变异与聚类分析

Analysis of cpDNA trnL-trnF sequences of Huperzia serrata var. longipetiolata of different geographical populations

采用直接测序法,对石杉科广布种长柄石杉(Huperzia serrata var.longipetiolata)21个居群(福建省19个居群和江西省2个居群)共计126株个体的叶绿体DNA trnL-trnF序列进行测序,用Clustal X和MEGA5.0软件进行序列分析,UPGMA法构建聚类图,以期了解序列变异与地理分布的关系,为长柄石杉资源的保护及开发利用提供参考依据.扩增获得的序列全长在928-967 bp之间,经排序后两端切平,序列长925 bp,G+C平均含量为34.05%;21个长柄石杉居群的cpDNA trnL-trnF序列存在20个变异位点,5个信息位点.UPGMA聚类结果显示,福建省居群与江西居群存在较大遗传距离,分聚为不同分支;福建省内19个居群再分聚为3个分支,其中11个居群间的遗传距离为零.研究结果表明长柄石杉居群间存在较明显的遗传分化和一定强度的基因流,居群间的叶绿体DNA trnL-trnF序列变异与地理分布尤其是山脉形成的隔离和屏障有关,较高的遗传多样性和基因流水平有利于长柄石杉种群的生存与进化.

This study aimed to investigate the relationship between the variation of chloroplast DNA（cpDNA）trnL-trnF gene sequences and the geographical origins of Huperzia serrata var. longipetiolata, so as to provide reference basis for its protection and utilization. PCR direct sequencing was applied to detect the chloroplast DNA trnL-trnF gene sequences of 126 samples collected from 21 populations （19 in Fujian and 2 in Jiangxi） of Huperzia serrata var. longipetiolata. Then sequence analysis was performed by means of Clustal X and MEGA 5.0. The cluster diagram was constructed by UPGMA method. The length of trnL-trnF of all samples was 928 - 967 bp; the aligned sequence length was 925 bp; and the average content of G ＋ C was 34.05%. There were 20 variable sites and 5 informative sites in these sequences. The cluster diagram by UPGMA method showed great variance between Fujian and Jiangxi geographical populations, which should be classified as different clusters. The 19 populations in Fujian were divided into three clusters, 11 of them with no genetic distance. The results indicated that genetic differentiation and gene flow of the populations of Huperzia serrata var. longipetiolata are in relatively high level, which is beneficial to the survival and evolution of the populations. The variation of trnL-trnF sequence of Huperzia serrata var. longipetiolata populations is related to their geographical distribution, especially related to the isolation of mountain ranges.