Inner Mongolia Key Laboratory of Environmental Pollution Control and Waste Resource Recycle, Ministry of Education Collaborative Innovation Center for Grassland Ecological Security, Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China.
Inner Mongolia Key Laboratory of Environmental Pollution Control and Waste Resource Recycle, Ministry of Education Collaborative Innovation Center for Grassland Ecological Security, Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China.
Sci Total Environ. 2024 Apr 20;922:171278. doi: 10.1016/j.scitotenv.2024.171278. Epub 2024 Feb 26.
Bio-organic fertilizer (BOF) was effective to promote the phytoremediation efficiency of heavy metal(loid)s-contaminated saline soil (HCSS) by improving rhizosphere soil properties, especially microbiome. However, there existed unclear impacts of BOF on plant metabolome and plant-driven manipulation on rhizosphere soil microbiota in HCSS, which were pivotal contributors to stress defense of plants trapped in adverse conditions. Here, a pot experiment was conducted to explore the mechanisms of BOF in improving alfalfa (Medicago sativa)-performing phytoremediation of HCSS. BOF application significantly increased the biomass (150.87-401.58 %) to support the augments of accumulation regarding heavy metal(loid)s (87.50 %-410.54 %) and salts (38.27 %-271.04 %) in alfalfa. BOF promoted nutrients and aggregates stability but declined pH of rhizosphere soil, accompanied by the boosts of rhizomicrobiota including increased activity, reshaped community structure, enriched plant growth promoting rhizobacteria (Blastococcus, Modestobacter, Actinophytocola, Bacillus, and Streptomyces), strengthened mycorrhizal symbiosis (Leohumicola, Funneliformis, and unclassified_f_Ceratobasidiaceae), optimized co-occurrence networks, and beneficial shift of keystones. The conjoint analysis of plant metabolome and physiological indices confirmed that BOF reprogrammed the metabolic processes (synthesis, catabolism, and long-distance transport of amino acid, lipid, carbohydrate, phytohormone, stress-resistant secondary metabolites, etc) and physiological functions (energy supply, photosynthesis, plant immunity, nutrients assimilation, etc) that are associated intimately. The consortium of root metabolome, soil metabolome, and soil microbiome revealed that BOF facilitated the exudation of metabolites correlated with rhizomicrobiota (structure, biomarker, and keystone) and rhizosphere oxidative status, e.g., fatty acyls, phenols, coumarins, phenylpropanoids, highlighting the plant-driven regulation on rhizosphere soil microbes and environment. By compiling various results and omics data, it was concluded that BOF favored the adaptation and phytoremediation efficiency of alfalfa by mediating the plant-soil-rhizomicrobiota interactions. The results would deepen understanding of the mechanisms by which BOF improved phytoremediation of HCSS, and provide theoretical guidance to soil amelioration and BOF application.
生物有机肥（BOF）通过改善根际土壤特性，特别是微生物组，有效促进了重金属（类）污染盐渍土壤（HCSS）的植物修复效率。然而，BOF 对植物代谢组的影响以及植物对 HCSS 根际土壤微生物群的驱动操纵尚不清楚，而这些因素是植物在逆境中应激防御的关键贡献者。在这里，进行了一项盆栽实验，以探索 BOF 提高紫花苜蓿（Medicago sativa）对 HCSS 植物修复能力的机制。BOF 的应用显著增加了生物量（150.87-401.58%），以支持重金属（类）（87.50%-410.54%）和盐分（38.27%-271.04%）在紫花苜蓿中的积累增加。BOF 促进了养分和团聚体的稳定性，但降低了根际土壤的 pH 值，同时增加了根际微生物群落的活力，改变了群落结构，丰富了植物促生根瘤菌（Blastococcus、Modestobacter、Actinophytocola、芽孢杆菌和链霉菌），增强了菌根共生关系（Leohumicola、Funneliformis 和未分类的_Ceratobasidiaceae），优化了共生网络，并有利于关键种的转变。植物代谢组和生理指标的联合分析证实，BOF 重新编程了与代谢过程（合成、分解代谢和氨基酸、脂质、碳水化合物、植物激素、抗逆次生代谢物等的长距离运输）和生理功能（能量供应、光合作用、植物免疫、养分同化等）密切相关的代谢过程。根代谢组、土壤代谢组和土壤微生物组的联合分析表明，BOF 促进了与根际微生物组（结构、生物标志物和关键种）和根际氧化状态相关的代谢物的分泌，例如脂肪酸、酚类、香豆素、苯丙素，突出了植物对根际土壤微生物和环境的调控作用。通过整合各种结果和组学数据，得出结论，BOF 通过调节植物-土壤-根际微生物群相互作用，有利于紫花苜蓿的适应和植物修复效率。研究结果将加深对 BOF 提高 HCSS 植物修复效率机制的理解，并为土壤改良和 BOF 应用提供理论指导。
