珍稀濒危植物硬叶兜兰的遗传多样性及遗传结构研究(英文)

ISSR and SRAP Markers Reveal Genetic Diversity and Population Structure of an Endangered Slipper Orchid,Paphiopedilum micranthum(Orchidaceae)

由于人为采集、走私贩卖以及生境的破坏,分布于中国西南石灰岩地区的野生硬叶兜兰居群受到严重的干扰与威胁。为有效地保护这种珍稀野生植物,本研究采用ISSR和SRAP两种分子标记对15个硬叶兜兰野生居群进行遗传多样性及遗传结构的研究。结果表明,硬叶兜兰在物种水平上具有较高的遗传多样性(ISSR:PPB=91.66%,H e=0.3839;SRAP:PPB=99.29%,H e=0.2806)。硬叶兜兰居群间存在一定程度的遗传分化(ISSR:G st=0.2577;SRAP:G st=0.2383),可能由于较低的基因流(ISSR:Nm=0.7201;SRAP:Nm=0.7991)所致。UPGMA聚类分析以及主成分分析均把15个居群分成2个主要分支。居群间的地理距离和海拔差距是引起居群遗传分化的自然因素。

Paphiopedilum micranthum is an endangered pink slipper orchid mainly distributed in the limestone areas of southwestern China. Wild populations of this species have been seriously threatened by excessive collections, ram- pant smuggling for export, and habitat destruction. We used 15 ISSR markers and 11 SRAP markers to investigate the genetic diversity and structure of 15 natural populations. A high degree of diversity was observed at the species level （ ISSR： PPB = 91.66%, He = 0. 3839 ; SRAP ： PPB = 99. 29%, He = 0. 2806）. Certain degree of genetic differ- entiation among populations （ ISSR ： Gst, = 0. 2577 ; SRAP ： Gst, = 0. 2383） was detected maybe caused by low gene flow （ ISSR ： Nm = 0. 7201 ; SRAP ： Nm = 0. 7991 ）. Consistent with the results of Principal Coordinate Analysis, the UPGMA dendrogram analysis divided the 15 populations into two main clades. In addition to geographic distance, the difference in elevation was another natural factor contributing to this differentiation. Knowledge about genetic di- versity and structure gained from our study will be beneficial for the development of reasonable and efficient strategies to conserve this endangered species.