In-depth characterization of the genetic diversity and population structure of wild relatives is of paramount importance for genetic improvement and biodiversity conservation, and is particularly crucial when the wild relatives of crops are endangered. In this study, we sampled the Alpine plum (Briançon apricot) Prunus brigantina Vill. across its natural distribution in the French Alps, where its populations are severely fragmented and its population size strongly impacted by humans. We analysed 71 wild P. brigantina samples with 24 nuclear simple sequence repeat (microsatellite) markers and studied their genetic diversity and population structure, with the aim to inform in situ conservation measures and build a core collection for long-term ex situ conservation. We also examined the genetic relationships of P. brigantina with other species in the Prunophora subgenus, encompassing the Prunus (Eurasian plums), Prunocerasus (North American plums) and Armeniaca (apricots) sections, to check its current taxonomy. We detected a moderate genetic diversity in P. brigantina and a Bayesian model–based clustering approach revealed the existence of three genetically differentiated clusters, endemic to three geographical regions in the Alps, which will be important for in situ conservation measures. Based on genetic diversity and population structure analyses, a subset of 36 accessions were selected for ex situ conservation in a core collection that encompasses the whole detected P. brigantina allelic diversity. Using a dataset of cultivated apricots and wild cherry plums (P. cerasifera) genotyped with the same markers, we detected gene flow neither with European P. armeniaca cultivars nor with diploid plums. Similar to previous studies, dendrograms and networks placed P. brigantina closer to the Armeniaca section than to the Prunus section. Our results thus confirm the classification of P. brigantina within the Armeniaca section; it also illustrates the importance of the sampling size and design in phylogenetic studies.

深入表征野生近缘种的遗传多样性和种群结构对于遗传改良和生物多样性保护至关重要，在作物野生近缘种受到威胁时尤其重要。在这项研究中，我们抽样了高山李子（Briançon杏）李李。分布在法国阿尔卑斯山的自然分布地区，那里的人口严重分散，人口规模受到人类的强烈影响。我们分析了71个野生Brigantina样本具有24个核简单序列重复（微卫星）标记，并研究了它们的遗传多样性和种群结构，目的是为就地保护提供信息，并为长期就地保护建立核心收藏。我们还检查了P. brigantina与李属亚种中其他物种的遗传关系，包括李属（欧亚李子），李属（北美李子）和亚美尼亚科（杏子）部分，以检查其当前的分类学。我们在P. brigantina中检测到中等遗传多样性以及基于贝叶斯模型的聚类方法揭示了三个遗传分化的簇的存在，这是阿尔卑斯山三个地理区域特有的，这对于现场保护措施很重要。根据遗传多样性和种群结构分析，选择了36个种质的一个子集进行核心保存，以对其进行异地保护，该种质涵盖整个检测到的Brigantina等位基因多样性。使用具有相同标记基因型的栽培杏和野生樱桃李（P. cerasifera）数据集，我们既未检测到欧洲P. armeniaca品种也未检测到二倍体李子的基因流。与先前的研究相似，树状图和网络放置了P. brigantina靠近亚美尼亚科（Armeniaca）部分，而不是李属（Prunus）部分。因此，我们的结果证实了所述分类P. brigantina的杏部内; 它还说明了样本量和设计在系统发育研究中的重要性。