秦岭山区美容杜鹃五个野生种群遗传多样性的ISSR分析

摘要

美容杜鹃是杜鹃花科杜鹃花属常绿观花植物,也是秦岭地区的特有属,在维持当地生态平衡方面发挥着重要作用,但目前资源正在遭受严重的破坏.该文通过 ISSR分子标记技术对秦岭地区5个美容杜鹃野生种群进行遗传多样性分析,了解美容杜鹃不同种群的遗传分化,从而为美容杜鹃野生种质资源保护策略的制定提供理论依据.用8个ISSR引物对5个天然种群的90个单株进行扩增,共扩增出78条带(平均每条引物产生9．75条带),其中65条带是多态的,多态位点占总位点的百分率为83％.种群总的 Nei’s 基因多样性指数为0．3386,Shannon信息多态性指数为0．4972,表明美容杜鹃总的遗传多样性水平较高.种群多态位点百分率为82．71％~90．25％,Shannon信息多态性指数为0．4161~0．5867,Nei’s 基因多样性指数为0．3044~0．4122,表明美容杜鹃不同种群遗传多样性水平差异较大.其中镇安木王种群和柞水牛背梁种群的遗传多样性水平较高.AMOVA分析表明种群内的遗传变异(91．22％)大于种群间的遗传变异(8．78％).UPGMA 聚类分析表明5个种群的遗传分化程度与地理距离没有相关性.因此建议尽可能地保护美容杜鹃所有的天然种群原生境条件,以最大限度保护其遗传变异.由于镇安和柞水种群具有较高的遗传多样性,因此建议优先对这2个种群实施就地保护和迁地保护.%Rhododendron calophytum belonged to Ericaceae family,Rhododendron genus.It is an endemic evergreen plant with beautiful flowers,and has high ornamental value and breeding value,which is also beneficial to maintain the stability of the ecosystem in Qinling Mountains.Recently,R.calophytum germplasm was endangered due to hu-man being’s excessive excavation activities.The genetic diversity of five natural populations of R.calophytum in Qinling Mountain was assessed using inter-simple sequence repeat (ISSR )markers.And 78 bands were amplified by 8 informative and reliable primers,of which 65 were polymorphic loci,the percentage of polymorphic bands was 83%.As analyzed by the software POPGENE,the genetic diversity difference among populations was high with PPL of 82.71%-90.25%,Nei’s gene diversity 0.3044-0.4122 and Shannon’s Information Index 0.4161-0.5867.Anal-ysis of molecular variance(AMOVA )revealed that among and within population genetic variations accounted for 8.78% and 91.22% of the total genetic variation,respectively.UPGMA cluster analysis based on Nei and Li genetic similarity did not form clades corresponding to geographic distance.Therefore,it is suggested that all the original habitat conditions of R.calophytum populations should be protected as much as possible in order to protect its genetic variation.In addition,we should take some measures of in-situ and ex-situ conservation to protect R.calophytum populations in Zhen’an and Zhashui because these two populations have much higher genetic diversity.