Collaborative Research: Metabolism and Transfer of Nitrogen in the Arbuscular Mycorrhizal Symbiosis

丛枝菌根共生是植物根系和土壤真菌之间的一种密切相互作用，对大约80%的已知植物物种的养分吸收是必不可少的。丛枝菌根真菌及其根外菌丝体为植物吸收磷酸盐和氮素等营养物质，并与植物的碳水化合物交换。然而，我们对参与氮素吸收和向寄主植物转移的代谢途径以及共生伙伴之间营养交换的调控的了解仍然有限。本项目的目标是了解丛枝菌根共生中的养分交换，这也是将丛枝菌根真菌作为生物肥料应用于可持续农业的关键。我们计划的实验方法包括稳定和放射性同位素标记、蛋白质定量和酶分析、基因表达研究以及蛋白质和元素定位技术，如免疫组织化学和能量色散X射线显微分析。这个项目将告诉我们在丛枝菌根共生中氮是如何处理的，以及共生中的氮通量是如何被调节的。受训人员，包括博士后、研究生和本科生，将学习范围异常广泛的现代生物技术，并将深入了解丛枝菌根共生及其对植物营养获取的重要性。

The arbuscular mycorrhizal symbiosis, a close interaction between plant roots and soil fungi, is essential for the nutrient uptake of approximately 80 % of all known plant species. The arbuscular mycorrhizal fungus with its extraradical mycelium takes up nutrients such as phosphate and nitrogen for the plant, and is supplied in exchange with carbohydrates from the plant. However, our knowledge of the metabolic pathways involved in nitrogen uptake and transfer to the host plant and about the regulation of nutrient exchange between the symbiotic partners is still limited. The goal of this project is to understand the exchange of nutrients in the arbuscular mycorrhizal symbiosis, which is also key to applying arbuscular mycorrhizal fungi as "biofertilizers" in sustainable agriculture. The experimental approach we plan includes stable and radioactive isotope labeling, protein quantification and enzymatic assays, gene expression studies and protein and elemental localization techniques such as immunohistochemistry and energy dispersive X-ray microanalysis. This project will tell us how nitrogen is handled in the arbuscular mycorrhizal symbiosis, and how the flux of nitrogen in the symbiosis is regulated. The trainees, including a postdoc, a graduate student and undergraduates will learn an unusually broad range of modern biological techniques and will gain insights into the arbuscular mycorrhizal symbiosis and its importance for the nutrient acquisition of plants.