Background and aims Plant-soil feedbacks are the result of multiple abiotic and biotic mechanisms. However, few studies have addressed how feedbacks vary based on abiotic context or attempted to identify microbiota responsible for feedbacks. We investigated whether plant-soil feedbacks of an ectomycorrhizal tree ( Quercus macrocarpa ) varied based on soil nutrient status and whether fungal community composition and diversity could explain feedback patterns. Methods We inoculated Q. macrocarpa seedlings with field-sampled soils taken from five soil origins – including heterospecific and conspecific trees and an old field – which were profiled using fungal DNA metabarcoding. Results There was a positive home vs. away plant-soil feedback, though feedbacks with individual hosts were not significant regardless of fertilization. Still, hosts harbored distinctive fungal communities that were predictive of plant growth. There was a growth promotive effect of ectomycorrhizal OTU diversity that was weakened with fertilization, suggesting context-dependent relationships between plant growth and a guild of fungal mutualists. Conclusions Our results demonstrate that the host-specific accumulation of functionally important soil microbes is not always sufficient to drive species level plant-soil feedbacks. Our data provide support for a role of ECM fungal diversity in mediating plant growth responses, though it is unclear whether this effect was direct or indirect.

中文翻译：

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尽管植物 - 土壤反馈弱，但外生菌根真菌多样性与土壤养分相互作用以预测植物生长

背景和目标植物-土壤反馈是多种非生物和生物机制的结果。然而，很少有研究解决反馈如何根据非生物环境变化或试图确定负责反馈的微生物群。我们调查了外生菌根树（ Quercus macrocarpa ）的植物-土壤反馈是否因土壤养分状况而异，以及真菌群落组成和多样性是否可以解释反馈模式。方法 我们用取自五个土壤来源的田间取样土壤接种 Q. macrocarpa 幼苗 - 包括异种和同种树木以及旧田 - 使用真菌 DNA 宏条形码进行分析。结果 有一个积极的家庭与外地植物 - 土壤反馈，尽管与施肥无关的个体宿主的反馈并不显着。仍然，宿主拥有独特的真菌群落，可以预测植物的生长。外生菌根 OTU 多样性的生长促进作用随着施肥而减弱，表明植物生长与真菌共生者协会之间存在环境依赖关系。结论我们的结果表明，功能重要的土壤微生物的宿主特异性积累并不总是足以驱动物种水平的植物-土壤反馈。我们的数据为 ECM 真菌多样性在介导植物生长反应中的作用提供了支持，尽管尚不清楚这种影响是直接的还是间接的。表明植物生长与真菌共生者协会之间的上下文相关关系。结论我们的结果表明，功能重要的土壤微生物的宿主特异性积累并不总是足以驱动物种水平的植物-土壤反馈。我们的数据为 ECM 真菌多样性在介导植物生长反应中的作用提供了支持，尽管尚不清楚这种影响是直接的还是间接的。表明植物生长与真菌共生者协会之间的上下文相关关系。结论我们的结果表明，功能重要的土壤微生物的宿主特异性积累并不总是足以驱动物种水平的植物-土壤反馈。我们的数据为 ECM 真菌多样性在介导植物生长反应中的作用提供了支持，尽管尚不清楚这种影响是直接的还是间接的。