Data from: Landscape genomics and a common garden trial reveal adaptive differentiation to temperature across Europe in the tree species Alnus glutinosa

The adaptive potential of tree species to cope with climate change has important ecological and economic implications. Many temperate tree species experience a wide range of environmental conditions, suggesting high adaptability to new environmental conditions. We investigated adaptation to regional climate in the drought-sensitive tree species Alnus glutinosa (Black alder), using a complementary approach that integrates genomic, phenotypic and landscape data. A total of 24 European populations were studied in a common garden and through landscape genomic approaches. Genotyping-By-Sequencing was used to identify SNPs across the genome, resulting in 1990 SNPs. Although a relatively low percentage of putative adaptive SNPs was detected (2.86% outlier SNPs), we observed clear associations among outlier allele frequencies, temperature, and plant traits. In line with the typical drought avoiding nature of A. glutinosa, leaf size varied according to a temperature gradient and significant associations with multiple outlier loci were observed, corroborating the ecological relevance of the observed outlier SNPs. Moreover, the lack of isolation-by-distance, the very low genetic differentiation among populations and the high intra-population genetic variation all support the notion that high gene exchange combined with strong environmental selection promotes adaptation to environmental cues.林木物种应对气候变化的适应潜力，具有重要的生态学与经济学意义。诸多温带林木物种需应对广泛的环境条件变化，这暗示其对新生环境具备较强的适应能力。本研究以对干旱敏感的林木物种欧洲黑桤木（Alnus glutinosa，Black alder）为研究对象，采用整合基因组学、表型组学与景观数据的互补研究方法，探究其对区域气候的适应机制。研究共纳入24个欧洲种群，通过同质园实验与景观基因组学技术开展分析。采用测序分型（Genotyping-By-Sequencing）技术对全基因组范围内的单核苷酸多态性（Single Nucleotide Polymorphism, SNP）进行鉴定，最终获得1990个有效SNP位点。尽管检测到的潜在适应性SNP占比相对较低（异常位点SNP仅占2.86%），但研究仍观察到异常等位基因频率、温度与植物性状之间存在清晰关联。结合欧洲黑桤木典型的避旱特性，叶面积随温度梯度发生显著变化，且与多个异常位点存在显著关联，这进一步佐证了所检测到的异常SNP位点的生态学相关性。此外，种群未表现出距离隔离（Isolation-by-Distance）效应、种群间遗传分化程度极低，以及种群内遗传变异水平较高，所有这些结果均支持“高水平基因交流与强烈的环境选择共同推动物种适应环境信号”这一结论。