Plant–microbe interactions are essential in shaping plant performance and overall ecosystem functioning. However, the regulatory mechanisms underlying plant–microbe interactions mediated by mycorrhizal symbiosis in saline–alkaline soils are still not fully understood. Here, we aimed to clarify the synergistic regulatory mechanism through which arbuscular mycorrhizal fungi (AMF) symbiosis drives the rhizosphere microbiome to improve perennial herbage growth in saline–alkaline soils and evaluate phytoremediation efficiency. This study revealed that Funneliformis mosseae inoculation (i) strongly promoted the growth of all three herbage species (with values ranging from 21.62% to 233.33%), Na+ accumulation in plants (with values ranging from 24.63% to 188.89%), and decreased soil electrical conductivity (with values ranging from 7.68% to 12.87%), potentially suggesting improved phytoremediation efficiency with AMF symbiosis; (ii) increased nutritional content and decreased C:P and N:P ratios (with values ranging from 27.20% to 92.87%) and improved K+/Na+ and P/Na+ ratios (with values ranging from 2.60% to 302.96%); (iii) increased the abundance of some beneficial bacterial taxa and strengthened the significant strong relationships among most of these bacteria and plant biomass, ion homeostasis as well as stoichiometric ratio constants, and AMF inoculation treatments also consisted the higher proportion of differential genera significantly correlated with these plant factors as well as plant nutrient contents, potentially reflecting that AMF mediated the enrichment process of beneficial bacterial taxa and may strength functional interaction between plant and bacterial taxa, which may be importance for the enhancement of saline–alkaline tolerance of plants; and (iv) enhanced stability of the rhizosphere bacterial community and complexity of interaction networks, and the related indictors also established significant correlations with plant/soil factors, suggesting that the improvement of stability and functional complexity driven by AMF may also be beneficial for enhancing phytoremediation efficiency. These findings indicate that AMF inoculation plays its own beneficial role by simultaneously activating the potential of beneficial rhizosphere bacterial taxa and that their synergistic interaction is more beneficial for enhancing plant growth in salt‐affected soils and enhancing phytoremediation efficiency. This study helps to elucidate the underlying mechanisms through which AMF‐mediated rhizosphere bacterial community improve plant growth and tolerance to saline–alkaline stresses, and provides evidence that effective ecological restoration of saline–alkaline degraded grasslands can be achieved via the use of mycorrhizal symbiosis herbage.

中文翻译：

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AMF共生驱动根际微生物群协同改善盐碱土壤中的牧草生长

植物与微生物的相互作用对于塑造植物性能和整体生态系统功能至关重要。然而，盐碱土壤中菌根共生介导的植物与微生物相互作用的调控机制仍不完全清楚。在这里，我们的目的是阐明丛枝菌根真菌（AMF）共生驱动根际微生物组改善盐碱土壤中多年生草本植物生长的协同调节机制并评估植物修复效率。这项研究表明苔藓漏斗形虫接种 (i) 强烈促进了所有三种牧草物种的生长（值范围为 21.62% 至 233.33%）、Na+植物中的积累（数值范围为24.63％至188.89％），并且土壤电导率降低（数值范围为7.68％至12.87％），这可能表明AMF共生可以提高植物修复效率； (ii) 增加营养成分并降低 C:P 和 N:P 比率（数值范围为 27.20% 至 92.87%）并提高 K+/钠+和P/Na+比率（值范围为 2.60% 至 302.96%）； (iii)增加了一些有益细菌类群的丰度，并加强了大多数这些细菌与植物生物量、离子稳态以及化学计量比常数之间的显着强关系，并且AMF接种处理还包括较高比例的差异属，与这些植物因子以及植物养分含量，可能反映出AMF介导了有益细菌类群的富集过程，并可能加强植物和细菌类群之间的功能相互作用，这可能对增强植物的耐盐碱能力具有重要意义； (iv) 根际细菌群落的稳定性和相互作用网络的复杂性增强，相关指标也与植物/土壤因素建立了显着的相关性，这表明AMF驱动的稳定性和功能复杂性的改善也可能有利于增强植物修复效率。这些发现表明，AMF接种通过同时激活有益根际细菌类群的潜力来发挥其自身的有益作用，并且它们的协同相互作用更有利于促进受盐影响土壤中的植物生长和提高植物修复效率。本研究有助于阐明AMF介导的根际细菌群落改善植物生长和盐碱胁迫耐受性的潜在机制，并为利用菌根共生牧草实现盐碱退化草地的有效生态恢复提供证据。