Analysis of genetic diversity and population structure of the endangered Origanum compactum from Morocco, using SSR markers: Implication for conservation
Analysis of genetic diversity and population structure of the endangered Origanum compactum from Morocco, using SSR markers: Implication for conservation
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DOI：
10.1016/j.biocon.2017.05.030
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发表时间：
2017-08-01
影响因子：
5.9
通讯作者：
Al Faiz, Chaouki
中科院分区：
文献类型：
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作者：
Aboukhalid, Kaoutar;Machon, Nathalie;Al Faiz, Chaouki
牛至是最受欢迎的药用和烹饪草本植物之一，具有悠久的传统使用历史，该物种为摩洛哥和西班牙南部特有，被认为是濒危物种，主要原因是过度捕捞和栖息地破坏。评估受威胁物种的遗传多态是种质保存的先决条件。为了支持和监测未来的保护和管理措施，我们使用了15个微卫星座位对分布在59个地点的670只紧凑型稻瘟病菌进行了基因分型，覆盖了摩洛哥该物种的整个地理分布。与以前大多数研究中所争论的相反，摩洛哥牛至的遗传多样性更大，主要是在孤立和下降的种群上，而不是较少碎片化的种质。因此，我们的研究根据它们的遗传多样性水平确定了与保护目的最相关的管理单位。物种的多年性、体细胞突变或多个创始人事件等因素可以解释这种濒危植物在物种水平上的意外遗传多样性水平。种群遗传结果反映了一个强大的遗传结构，并在致密野生稻种群中发现了三个主要聚类群：一个北方聚类群，由直布罗陀海峡附近的种群(丹吉尔-特图安和切夫查乌恩地区以及来自陶纳特的一些邻近种群)组成，以及另外两个具有明显混合血统的聚类群。这一结果支持了直布罗陀海峡可能是西班牙南部和摩洛哥北部之间植物迁徙路线的假设。种群的高度分化(Fst=0.22)和种群间的低基因流动率(Nm=0.88)可能是由于最近通过栖息地干扰对种群的隔离造成的。使用广义逐步突变模型(SSM)和两阶段模型(TPM)使用最大似然法推断的历史人口模式显示，59个抽样人口中的39个过去有显著的人口统计学变化。这些结果的意义，以制定适当的保护策略，该濒危物种被提出。
Origanum compactum L. (Lamiaceae) is one of the most popular medicinal and culinary herbs with a long history of traditional use, This species, endemic to Morocco and Southern Spain, is considered as threatened, due mainly to over-harvesting and habitat destruction. Assessment of genetic polymorphism of threatened species constitutes a prerequisite for germplasm conservation. To support and monitor future conservation and management measures, we used 15 microsatellite loci to genotype 670 individuals of O. compactum distributed over 59 localities covering the entire geographic distribution of the species in Morocco. In contrast to what was argued in most previous studies, the genetic diversity of the Moroccan oregano was greater mostly on isolated and declined populations compared to less fragmented accessions. Accordingly, our study identifies the most relevant management units for conservation purposes on the basis of their genetic diversity level. Factors such as the perennity of the species, somatic mutations, or multiple founder events could explain this unexpected level of genetic diversity at the species level in this endangered plant. The population genetic results reflect a strong genetic structure and identify three major clusters among O. compactum populations: a Northern cluster composed of populations near the strait of Gibraltar (Tangier-Tetouan and Chefchaouen regions as well as some adjacent populations from Taounate), and two other clusters with significant mixed lineage. This result supports the hypothesis that the strait of Gibraltar could be a migration route for plants between Southern Spain and Northern Morocco. The high differentiation of populations (Fst = 0.22) and the low rate of gene flow between them (Nm = 0.88) might been caused by recent isolation of the populations through habitat disturbances. Historical demographic patterns inferred with a generalized stepwise mutation model (SSM) and two-phase model (TPM) using maximum likelihood showed significant past demographic changes in 39 of the 59 sampled populations. Implications of these results to develop appropriate conservation strategies of this endangered species are proposed.