Does resource exchange in ectomycorrhizal symbiosis vary with competitive context and nitrogen addition?
Does resource exchange in ectomycorrhizal symbiosis vary with competitive context and nitrogen addition?
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DOI：
10.1111/nph.17871
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发表时间：
2021-12-07
期刊：
影响因子：
9.4
通讯作者：
Peay, Kabir G.
中科院分区：
文献类型：
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作者：
Bogar, Laura M.;Tavasieff, Oceana S.;Peay, Kabir G.
外生菌根共生对大多数温带森林树木的营养至关重要，并有助于调节森林生态系统中碳（C）和氮（N）的运动。然而，控制植物碳与真菌氮交换的因素仍然不清楚。由于竞争和土壤资源可能会影响外生菌根资源的运动，我们进行了10个月的分根微观宇宙的研究，使用松muricata幼苗与Thelephora terrestris，刺乳牛肝菌，或没有外生菌根真菌，在两个N浓度在人工土壤中。真菌直接与根竞争，也间接与根竞争。我们使用稳定同位素富集来追踪植物光合产物和真菌N。对于T. terrestris，植物收到N相称的C给他们的真菌合作伙伴。在高氮条件下，土生革兰是一个上级互惠者。对于鼠伤寒沙门氏刺根、植物C和真菌N交换不耦合。而在低氮条件下，植物优先将C分配给S。pungens而不是T. terrestris。我们的研究结果表明，外生菌根资源转移取决于竞争和营养环境。植物可以用真菌氮交换碳，但这些资源的耦合取决于真菌种类和土壤氮。了解真菌策略的多样性，以及它们如何随环境背景而变化，揭示了驱动这种重要共生的机制。
Ectomycorrhizal symbiosis is essential for the nutrition of most temperate forest trees and helps regulate the movement of carbon (C) and nitrogen (N) through forested ecosystems. The factors governing the exchange of plant C for fungal N, however, remain obscure. Because competition and soil resources may influence ectomycorrhizal resource movement, we performed a 10-month split-root microcosm study using Pinus muricata seedlings with Thelephora terrestris, Suillus pungens, or no ectomycorrhizal fungus, under two N concentrations in artificial soil. Fungi competed directly with roots and indirectly with each other. We used stable isotope enrichment to track plant photosynthate and fungal N. For T. terrestris, plants received N commensurate with the C given to their fungal partners. Thelephora terrestris was a superior mutualist under high-N conditions. For S. pungens, plant C and fungal N exchange were not coupled. However, in low-N conditions, plants preferentially allocated C to S. pungens rather than T. terrestris. Our results suggest that ectomycorrhizal resource transfer depends on competitive and nutritional context. Plants can exchange C for fungal N, but coupling of these resources can depend on the fungal species and soil N. Understanding the diversity of fungal strategies, and how they change with environmental context, reveals mechanisms driving this important symbiosis.