Croll Daniel, McDonald Bruce A
Plant Pathology, Institute of Integrative Biology, ETH Zurich, 8092, Zurich, Switzerland.
Mol Ecol. 2017 Apr;26(7):2027-2040. doi: 10.1111/mec.13870. Epub 2016 Oct 24.
Local adaptation plays a key role in the evolutionary trajectory of host-pathogen interactions. However, the genetic architecture of local adaptation in host-pathogen systems is poorly understood. Fungal plant pathogens in agricultural ecosystems provide highly tractable models to quantify phenotypes and map traits to corresponding genomic loci. The outcome of crop-pathogen interactions is thought to be governed largely by gene-for-gene interactions. However, recent studies showed that virulence can be governed by quantitative trait loci and that many abiotic factors contribute to the outcome of the interaction. After introducing concepts of local adaptation and presenting examples from wild plant pathosystems, we focus this review on a major pathogen of wheat, Zymoseptoria tritici, to show how a multitude of traits can affect local adaptation. Zymoseptoria tritici adapted to different thermal environments across its distribution range, indicating that thermal adaptation may limit effective dispersal to different climates. The application of fungicides led to the rapid evolution of multiple, independent resistant populations. The degree of colony melanization showed strong pleiotropic effects with other traits, including trade-offs with colony growth rates and fungicide sensitivity. The success of the pathogen on its host can be assessed quantitatively by counting pathogen reproductive structures and measuring host damage based on necrotic lesions. Interestingly, these two traits can be weakly correlated and depend both on host and pathogen genotypes. Quantitative trait mapping studies showed that the genetic architecture of locally adapted traits varies from single loci with large effects to many loci with small individual effects. We discuss how local adaptation could hinder or accelerate the development of epidemics in agricultural ecosystems.
局部适应性在宿主 - 病原体相互作用的进化轨迹中起着关键作用。然而，人们对宿主 - 病原体系统中局部适应性的遗传结构了解甚少。农业生态系统中的真菌植物病原体提供了易于处理的模型，可用于量化表型并将性状映射到相应的基因组位点。作物 - 病原体相互作用的结果被认为主要由基因对基因的相互作用控制。然而，最近的研究表明，毒力可能由数量性状位点控制，并且许多非生物因素也会影响相互作用的结果。在介绍了局部适应性的概念并列举了野生植物病理系统的例子后，我们将本综述聚焦于小麦的一种主要病原体——小麦壳针孢，以展示多种性状如何影响局部适应性。小麦壳针孢在其分布范围内适应了不同的热环境，这表明热适应性可能会限制其向不同气候的有效扩散。杀菌剂的应用导致了多个独立抗性种群的快速进化。菌落黑化程度与其他性状表现出强烈的多效性，包括与菌落生长速率和杀菌剂敏感性的权衡。病原体在其宿主上的成功可以通过计算病原体繁殖结构并基于坏死病斑测量宿主损伤来定量评估。有趣的是，这两个性状可能相关性较弱，并且都取决于宿主和病原体的基因型。数量性状定位研究表明，局部适应性状的遗传结构从具有大效应的单个位点到具有小个体效应的多个位点各不相同。我们讨论了局部适应性如何阻碍或加速农业生态系统中病害的发展。
