Arbuscular mycorrhizal fungi (AMF) are ubiquitous in cultivated soils, forming symbiotic relationships with the roots of major crop species. Although studies in controlled conditions have demonstrated the potential of the symbiosis to enhance host plant nutrition and alleviate environmental stress, practical difficulties make it hard to estimate the actual benefit in cultivated fields, not least because of the lack of availability of suitable AMF-free controls. Furthermore, the response can vary depending on the plant variety in a manner which is not fully understood. Here, we implemented a novel strategy based on the selective incorporation of AMF-resistance into a genetic mapping population to evaluate maize response in the field. We found AMF to account for about one third of the grain production in a rain-fed medium input field, as well as to impact the relative performance of plant varieties. Characterization of the genetic architecture of host response allowed us to distinguish mycorrhizal benefit from dependence and indicated a trade-off between mycorrhizal and non-mycorrhizal performance, both at the level of individual QTL and genomewide. This approach is applicable to other crop species, permits further mechanistic analysis and is scalable to full yield trials.

中文翻译：

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宿主反应的遗传结构揭示了丛枝菌根对玉米栽培的重要性

丛枝菌根真菌（AMF）在耕作土壤中无处不在，与主要农作物物种的根形成共生关系。尽管在受控条件下的研究表明共生可能增强宿主植物的营养并减轻环境压力，但实际困难使人们难以估算耕地的实际效益，尤其是因为缺乏合适的无AMF的控制措施。此外，响应可以以植物的种类而变化，其方式尚不完全清楚。在这里，我们实施了一种基于将AMF抗性选择性整合到基因作图种群中的新策略，以评估田间玉米的反应。我们发现，AMF在雨水培养基输入领域中约占谷物产量的三分之一，以及影响植物品种的相对表现。宿主反应的遗传结构的表征使我们能够区分菌根受益与依赖性，并指出了在个体QTL水平和全基因组范围内，菌根性能与非菌根性能之间的权衡。这种方法适用于其他农作物，可以进行进一步的机械分析，并且可以扩展到全产量试验。