PDF(Pubmed)
Abstract：
Arbuscular mycorrhizal (AM) fungi engage in symbiosis with more than 80% of terrestrial plants, enlarging root phosphorus (P) absorption volume by producing extensive extraradical hyphae (ERH) in the soil. In addition, AM fungi recruit and cooperate with soil bacteria to enhance soil organic P mobilization and improve fungal and plant fitness through hyphal exudates. However, the role of the dominant compounds in the hyphal exudates in enhancing organic P mobilization in the mycorrhizal pathway is still not well understood. In this study, we added sugars, i.e., glucose, fructose, and trehalose, which are detected in the hyphal exudates, to the hyphal compartments (HCs) that allowed the ERH of the AM fungus to grow or not. The results showed that in AM fungus-inoculated pots, adding three sugars at a concentration of 2 mmol C kg-1 soil significantly increased the phosphatase activity and facilitated the mobilization of organic P in the HCs. The addition of fructose at a concentration of 2 mmol C kg-1 soil was the most efficient in increasing the phosphatase activity and enhancing organic P mobilization. The released inorganic P was then absorbed by the ERH of the AM fungus. The enhanced mobilization of organic P was correlated with the increase in phoD gene number and the changing bacterial community in the presence of fungal hyphae. The sugar addition enriched the relative abundance of some bacterial taxa, e.g., Betaproteobacteriales. Our study suggested that the addition of the sugars by mycorrhizae could be a pivotal strategy in managing P uptake in agricultural production, potentially directing future practices to optimize plant-fungi-bacteria interactions for improved P use efficiency.
摘要：
丛枝菌根(AM)真菌与80%以上的陆生植物共生,通过在土壤中产生大量的根外菌丝（ERH）来扩大根磷（P）的吸收量。此外,AM真菌通过菌丝分泌物招募并与土壤细菌合作，以增强土壤有机P的动员并改善真菌和植物的适应性。然而,菌丝分泌物中主要化合物在增强菌根途径中有机P动员中的作用尚不清楚。在这项研究中,我们添加了糖，即，葡萄糖，果糖,和海藻糖,在菌丝分泌物中检测到，菌丝隔室（HCs）允许AM真菌的ERH生长或不生长。结果表明,在接种AM真菌的盆中,以2mmolCkg-1的浓度添加三种糖，可显着提高磷酸酶活性，并促进有机P在HC中的动员。在2mmolCkg-1土壤中添加果糖对增加磷酸酶活性和增强有机P动员最有效。释放的无机P然后被AM真菌的ERH吸收。在存在真菌菌丝的情况下，有机P的增强动员与phoD基因数量的增加和细菌群落的变化有关。糖的添加丰富了一些细菌类群的相对丰度，例如，变形杆菌。我们的研究表明，菌根添加糖可能是管理农业生产中磷吸收的关键策略，有可能指导未来的实践来优化植物-真菌-细菌的相互作用，以提高磷的利用效率。
