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

丛枝菌根共生是植物根系与土壤真菌之间的密切相互作用，是所有已知植物物种中约80%的养分吸收所必需的。丛枝菌根真菌及其根外菌丝体为植物吸收营养物质如磷酸盐和氮，并与来自植物的碳水化合物交换供应。然而，我们的知识参与氮的吸收和转移到宿主植物的代谢途径和共生伙伴之间的营养交换的调节仍然有限。该项目的目标是了解丛枝菌根共生中的营养交换，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，蛋白质定量和酶测定，基因表达研究和蛋白质和元素定位技术，如免疫组织化学和能量色散X射线微分析。这个项目将告诉我们氮在丛枝菌根共生体中是如何处理的，以及共生体中氮的通量是如何调节的。包括博士后，研究生和本科生在内的学员将学习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.