Laboratoire des Interactions Plantes-Microbes-Environnement, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, CNRS, Université de Toulouse, Castanet-Tolosan, France.
Department of Systematic and Evolutionary Botany, University of Zürich, Zürich, Switzerland.
PLoS One. 2022 Oct 3;17(10):e0274561. doi: 10.1371/journal.pone.0274561. eCollection 2022.
Pathogens are often the main selective agents acting in plant communities, thereby influencing the distribution of polymorphism at loci affecting resistance within and among natural plant populations. In addition, the outcome of plant-pathogen interactions can be drastically affected by abiotic and biotic factors at different spatial and temporal grains. The characterization of the adaptive genetic architecture of disease resistance in native heterogeneous environments is however still missing. In this study, we conducted an in situ Genome-Wide Association study in the spatially heterogeneous native habitat of a highly genetically polymorphic local mapping population of Arabidopsis thaliana, to unravel the adaptive genetic architecture of quantitative disease resistance. Disease resistance largely differed among three native soils and was affected by the presence of the grass Poa annua. The observation of strong crossing reactions norms among the 195 A. thaliana genotypes for disease resistance among micro-habitats, combined with a negative fecundity-disease resistance relationship in each micro-habitat, suggest that alternative local genotypes of A. thaliana are favored under contrasting environmental conditions at the scale of few meters. A complex genetic architecture was detected for disease resistance and fecundity. However, only few QTLs were common between these two traits. Heterogeneous selection in this local population should therefore promote the maintenance of polymorphism at only few candidate resistance genes.
病原体通常是作用于植物群落的主要选择因子，从而影响影响自然植物种群内和种群间抗性相关基因座多态性的分布。此外，植物-病原体相互作用的结果可以受到不同时空尺度上的非生物和生物因素的极大影响。然而，在本地异质环境中，疾病抗性的适应性遗传结构的特征仍然缺失。在这项研究中，我们在高度遗传多态性的拟南芥本地局部映射种群的空间异质原生栖息地中进行了原位全基因组关联研究，以揭示定量疾病抗性的适应性遗传结构。疾病抗性在三种原生土壤之间存在很大差异，并且受到草 Poa annua 的存在的影响。在微生境中观察到 195 种拟南芥基因型之间的强烈交叉反应规范，同时在每个微生境中观察到繁殖力-疾病抗性的负相关关系，表明在几米线的尺度上，替代的本地拟南芥基因型在对比的环境条件下是有利的。对疾病抗性和繁殖力的检测都发现了复杂的遗传结构。然而，这两个特征之间只有少数 QTL 是共同的。在这个本地群体中，异质选择应该促进仅少数候选抗性基因的多态性的维持。
