Roschanski Anna M, Csilléry Katalin, Liepelt Sascha, Oddou-Muratorio Sylvie, Ziegenhagen Birgit, Huard Frédéric, Ullrich Kristian K, Postolache Dragos, Vendramin Giovanni G, Fady Bruno
Conservation Biology, Faculty of Biology, University of Marburg, Karl-von-Frisch-Straße, Marburg, 35032, Germany.
INRA, UR629, Ecologie des Forêts Méditerranéennes (URFM), Avignon Cedex 9, 84914, France.
Mol Ecol. 2016 Feb;25(3):776-94. doi: 10.1111/mec.13516.
Understanding local adaptation in forest trees is currently a key research and societal priority. Geographically and ecologically marginal populations provide ideal case studies, because environmental stress along with reduced gene flow can facilitate the establishment of locally adapted populations. We sampled European silver fir (Abies alba Mill.) trees in the French Mediterranean Alps, along the margin of its distribution range, from pairs of high- and low-elevation plots on four different mountains situated along a 170-km east-west transect. The analysis of 267 SNP loci from 175 candidate genes suggested a neutral pattern of east-west isolation by distance among mountain sites. F(ST) outlier tests revealed 16 SNPs that showed patterns of divergent selection. Plot climate was characterized using both in situ measurements and gridded data that revealed marked differences between and within mountains with different trends depending on the season. Association between allelic frequencies and bioclimatic variables revealed eight genes that contained candidate SNPs, of which two were also detected using F(ST) outlier methods. All SNPs were associated with winter drought, and one of them showed strong evidence of selection with respect to elevation. Q(ST)-F(ST) tests for fitness-related traits measured in a common garden suggested adaptive divergence for the date of bud flush and for growth rate. Overall, our results suggest a complex adaptive picture for A. alba in the southern French Alps where, during the east-to-west Holocene recolonization, locally advantageous genetic variants established at both the landscape and local scales.
了解森林树木的局部适应性是当前关键的研究重点和社会优先事项。地理和生态边缘种群提供了理想的案例研究，因为环境压力以及基因流减少有助于建立局部适应的种群。我们在法国地中海阿尔卑斯山沿其分布范围边缘，从位于一条东西向170公里长的样带上的四座不同山脉的高海拔和低海拔样地对中采集了欧洲银冷杉（Abies alba Mill.）树木样本。对来自175个候选基因的267个单核苷酸多态性（SNP）位点的分析表明，山区之间存在中性的东西向距离隔离模式。F(ST) 离群值检验揭示了16个显示出趋异选择模式的SNP。利用原位测量和网格化数据对样地气候进行了特征描述，结果显示不同山脉之间以及山脉内部存在显著差异，且趋势因季节而异。等位基因频率与生物气候变量之间的关联揭示了八个包含候选SNP的基因，其中两个也通过F(ST) 离群值方法检测到。所有SNP均与冬季干旱有关，其中一个在海拔方面显示出强烈的选择证据。在一个共同花园中对与适应性相关性状进行的Q(ST)-F(ST) 检验表明，芽萌动日期和生长速率存在适应性分化。总体而言，我们的结果表明，在法国南部阿尔卑斯山的欧洲银冷杉存在复杂的适应情况，在全新世从东向西的重新定殖过程中，在景观和局部尺度上都建立了局部有利的遗传变异。
