Manganese facilitates cadmium stabilization through physicochemical dynamics and amino acid accumulation in rice rhizosphere under flood-associated low pe plus pH

作     者：Wang, Meng Wang, Lifu Zhao, Shuwen Li, Shanshan Lei, Xiaoqin Qin, Luyao Sun, Xiaoyi Chen, Shibao 

作者机构：Chinese Acad Agr Sci Inst Agr Resources & Reg Planning Minist Agr & Rural Affairs Key Lab Plant Nutr & Fertilizer 12 Zhongguancun South St Beijing 100081 Peoples R China 

出 版 物：《JOURNAL OF HAZARDOUS MATERIALS》 (危险物资杂志)

年 卷 期：2021年第416卷

页      面：126079-126079页

核心收录：

学科分类：0830[工学-环境科学与工程（可授工学、理学、农学学位）] 08[工学] 

基　　金：National Natural Science Foundation of China National Key Research and Development Program of China [2020YFC1806300-04] 

主　　题：Metabolic profiles Amino acid secretion Soil cadmium availability Paddy soil Soil pe plus pH variation 

摘      要：Periodic flooding in paddy soils impacts redox behavior and induces variations in pe+pH levels. Manganese (Mn) is capable of reducing cadmium (Cd) uptake by rice. However, the processes involved in how Mn alters Cd mobilization under different pe+pH environments remain poorly understood. To investigate the mechanisms of Mn-mediated soil Cd-stabilization and subsequent inhibition of Cd uptake from flooded soils, we examined Cd immobilization in soil pot incubations, transcriptional changes in Cd-transport genes, and metabolomic analyses of roots and rhizosphere soils with or without Mn application. We found a decrease in extractable Cd concentration largely depended on irrigation-associated low pe+pH, exogenous Mn enhancement of Fe-Mn (oxyhydro) oxide-mediated Cd transformation, and Cd deposition in rice Fe/Mn plaques. Mn application led to striking effects on the expression of Cd-related genes eg. IRT, HMA, and NRAMP in rice root tissue. Exposure to Mn under variable pe+pH levels resulted in metabolic reprogramming of soil and rice roots. Mn induced amino acid synthesis in rice roots, leading to rhizosphere accumulation of free L-lysine, glycine, and glutamine, which can reportedly bind metal ions, forming complexes with Cd. Thus, secreted amino acids, low pe+pH, and free Mn can together comprise a multi-faceted approach to managing Cd toxicity in rice.