Summary Plant root exudates are involved in nutrient acquisition, microbial partnerships, and inter‐organism signaling. Yet, little is known about the genetic and environmental drivers of root exudate variation at large geographical scales, which may help understand the evolutionary trajectories of plants in heterogeneous environments. We quantified natural variation in the chemical composition of Arabidopsis thaliana root exudates in 105 Iberian accessions. We identified up to 373 putative compounds using ultra‐high‐performance liquid chromatography coupled with mass spectrometry. We estimated the broad‐sense heritability of compounds and conducted a genome‐wide association (GWA) study. We associated variation in root exudates to variation in geographic, environmental, life history, and genetic attributes of Iberian accessions. Only 25 of 373 compounds exhibited broad‐sense heritability values significantly different from zero. GWA analysis identified polymorphisms associated with 12 root exudate compounds and 26 known genes involved in metabolism, defense, signaling, and nutrient transport. The genetic structure influenced root exudate composition involving terpenoids. We detected five terpenoids related to plant defense significantly varying in mean abundances in two genetic clusters. Our study provides first insights into the extent of root exudate natural variation at a regional scale depicting a diversified evolutionary trajectory among A. thaliana genetic clusters chiefly mediated by terpenoid composition.

中文翻译：

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伊比利亚半岛遗传结构拟南芥根系分泌物组成的自然变化


摘要 植物根系分泌物参与营养获取、微生物伙伴关系和生物体间信号传导。然而，人们对大地理尺度上根系分泌物变异的遗传和环境驱动因素知之甚少，这可能有助于理解植物在异质环境中的进化轨迹。我们量化了 105 个伊比利亚种质中拟南芥根分泌物化学成分的自然变化。我们使用超高效液相色谱-质谱联用鉴定了多达 373 种推定化合物。我们估计了化合物的广义遗传力并进行了全基因组关联 （GWA） 研究。我们将根系分泌物的变异与伊比利亚种质的地理、环境、生活史和遗传属性的变异联系起来。373 种化合物中只有 25 种表现出与零显著不同的广义遗传力值。GWA 分析确定了与 12 种根系分泌物化合物和 26 个已知基因相关的多态性，这些基因参与代谢、防御、信号传导和营养物质运输。遗传结构影响涉及萜类化合物的根系分泌物组成。我们在两个遗传簇中检测到 5 种与植物防御相关的萜类化合物的平均丰度显著变化。我们的研究首次了解了区域尺度上根系渗出物自然变异的程度，描绘了主要由萜类化合物组成介导的拟南芥遗传簇之间的多样化进化轨迹。