Attributing functions to ectomycorrhizal fungal identities in assemblages for nitrogen acquisition under stress
Attributing functions to ectomycorrhizal fungal identities in assemblages for nitrogen acquisition under stress
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DOI：
10.1038/ismej.2013.158
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发表时间：
2014-02-01
期刊：
影响因子：
11
通讯作者：
Polle, Andrea
中科院分区：
文献类型：
--
作者：
Pena, Rodica;Polle, Andrea
菌根真菌在氮（N）循环中具有关键作用，特别是在北方和温带生态系统中。然而，外生菌根真菌（EMF）多样性的重要意义，这一重要的生态系统功能是未知的。在这里，EMF类群特定的N吸收进行了分析，通过N-15同位素富集在复杂的根相关的组合和非菌根根尖在对照实验。N-15在外生菌根中的富集程度取决于真菌的种类，外生菌根中的N-15代表了N的流入和输出，以及N-15与根尖N库的交换。光或水分剥夺揭示种间反应的多样性N吸收。部分分类特定的N通量外生菌根进行了评估，并估计的EMF组合植物N营养的好处。我们表明，外生菌根组合提供的优势，无机氮的吸收相比，非菌根根在环境约束下，但不为非胁迫植物。这些好处是通过应力激活不同的EMF类群，这表明显着的功能多样性EMF组合内实现的。我们开发并验证了一个模型，预测净N通量到植物的基础上，分类特定的N-15富集外生菌根根尖。这些结果开辟了一个新的途径来表征复杂的社区EMF类群的功能特征。
Mycorrhizal fungi have a key role in nitrogen (N) cycling, particularly in boreal and temperate ecosystems. However, the significance of ectomycorrhizal fungal (EMF) diversity for this important ecosystem function is unknown. Here, EMF taxon-specific N uptake was analyzed via N-15 isotope enrichment in complex root-associated assemblages and non-mycorrhizal root tips in controlled experiments. Specific N-15 enrichment in ectomycorrhizas, which represents the N influx and export, as well as the exchange of N-15 with the N pool of the root tip, was dependent on the fungal identity. Light or water deprivation revealed interspecific response diversity for N uptake. Partial taxon-specific N fluxes for ectomycorrhizas were assessed, and the benefits of EMF assemblages for plant N nutrition were estimated. We demonstrated that ectomycorrhizal assemblages provide advantages for inorganic N uptake compared with non-mycorrhizal roots under environmental constraints but not for unstressed plants. These benefits were realized via stress activation of distinct EMF taxa, which suggests significant functional diversity within EMF assemblages. We developed and validated a model that predicts net N flux into the plant based on taxon-specific N-15 enrichment in ectomycorrhizal root tips. These results open a new avenue to characterize the functional traits of EMF taxa in complex communities.