Water shortage can limit plant growth, which can be ameliorated by arbuscular mycorrhizal (AM) symbiosis through physiological and metabolic regulations. Deciphering which physiological and metabolic processes are central for AM-mediated regulations is essential for applications of mycorrhizal biotechnology in dryland agriculture. In this study, the influence of AM symbiosis on growth performance, photosynthesis, and organ accumulation of key C and N metabolites were assessed by growing maize (Mo17, Lancaster Sure Crop) seedlings inoculated with or without AM fungus (Rhizophagus irregularis Schenck & Smith BGC AH01) under different water regimes in greenhouse. Drought stress reduced shoot growth, while AM symbiosis significantly improved growth performances, with significant changes of photochemical processes and organ concentration of the key metabolites. AM symbiosis increased root levels of the metabolites in ornithine cycle and unsaturation of fatty acids regardless of water conditions. Root putrescine (Put) concentration was higher in AM than non-inoculated (NM) plants under well-watered conditions; the conversion of Put via diamine oxidase to γ-aminobutyric acid (GABA) occurred in roots of AM plants under drought stress. Leaf concentration of Put, the tricarboxylic acids, and soluble sugars significantly increased in AM plants under drought stress, showing higher values compared to that of NM plants. Moreover, photosystem II efficiency and chlorophyll concentration were higher in AM than NM plants regardless of water status. Fatty acid- and ornithine cycle-related metabolites along with soluble sugars, Put, and GABA were the key metabolites of AM-mediated regulations in response to drought stress.

中文翻译：

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丛枝菌根通过改变光系统II效率和关键代谢产物的水平来提高玉米幼苗的抗旱性

缺水会限制植物的生长，丛枝菌根（AM）共生可以通过生理和代谢调节来改善。对于菌根生物技术在旱地农业中的应用而言，确定哪种生理和代谢过程是增材制造介导的调节的核心是至关重要的。在这项研究中，通过接种或不接种AM真菌（不规则根瘤菌Schenck＆Smith BGC）的玉米（Mo17，Lancaster Sure Crop）生长幼苗，评估了AM共生对生长性能，光合作用和关键C和N代谢器官积累的影响。 AH01）在温室中的不同水分状况下。干旱胁迫减少了枝条的生长，而AM共生显着改善了生长性能，与光化学过程和重要代谢产物器官浓度的显着变化。AM共生增加了鸟氨酸循环中代谢物的根水平，并增加了脂肪酸的不饱和度，而与水的状况无关。在浇水良好的条件下，AM中的腐胺（Put）浓度高于未接种的（NM）植物。在干旱胁迫下，AM植物根系中Put通过二胺氧化酶转化为γ-氨基丁酸（GABA）。在干旱胁迫下，AM植物的Put，三羧酸和可溶性糖的叶片浓度显着增加，与NM植物相比，显示出更高的值。此外，无论水分状况如何，AM中的光系统II效率和叶绿素浓度均高于NM植​​物。