Lanthanum(III)-amino acid chelate mitigates copper(II) stress in rice (Oryza sativa)

• Published in: Scientific reports Vol. 14; no. 1; pp. 22315 - 13
• Main Authors: Chen, Jiajia, Zhong, Yuqing
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 27-09-2024; Nature Publishing Group; Nature Portfolio
• Subjects: 631/45; 631/45/603; Acidic soils; Agricultural production; Amino acid; Amino acids; Amino Acids - chemistry; Amino Acids - metabolism; Bioavailability; Chelate; Chelates; Chelating Agents - chemistry; Chelating Agents - pharmacology; Copper; Copper - chemistry; Detoxification; Electron microscopes; Environmental risk; Enzymes; Heavy metals; Humanities and Social Sciences; Hydrolysates; Immobilization; Lanthanum; Lanthanum - chemistry; Lanthanum - pharmacology; Ligands; Metals; multidisciplinary; Nanoparticles; Oryza - drug effects; Oryza - metabolism; Oryza sativa; Plant protection; Proteins; Rare earth; Rare earth elements; Rice; Rice (Oryza sativa); Science; Science (multidisciplinary); Seedlings; Soybeans; Stress, Physiological - drug effects; Transmission electron microscopy; Amino acid; Lanthanum; Rare earth; Copper; Chelate; Rice; Rice (Oryza sativa)
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-024-73771-4

Lanthanum (La(III)) is recognized for its ability to mitigate heavy metal stress in plants. However, the inorganic La(III) salts and lanthanum oxide nanoparticles (La
2
O
3
NPs) extensively used in agriculture are prone to soil immobilization, thereby compromising their bioavailability and posing environmental risks. This study synthesized and characterized the lanthanum(III)-amino acid chelate (La(III)-AA) from soybean protein isolate (SPI) hydrolysates. Maximum chelating rate (94.95%) was achieved under the conditions of mole ratio 1:1.5, pH 8.0, 50 ℃ and 5 h. Glu, Asp and Pro represent the primary La(III)-binding ligands. UV-vis and FTIR demonstrated that amino nitrogen and carboxyl oxygen participate in metal-ligand recognition. Scanning and Transmission electron microscopy showed that La(III) chelates with amino acids in a core-shell structure of uniform size. Consequently, a proposed chemical structure for the La(III)-AA complex was presented. A concentration of 20 mg/L La(III)-AA outperforms inorganic La salts in growth promotion and Cu detoxification. La(III)-AA significantly reduces the content of Cu (II) in rice tissues and enhances seedling tolerance to Cu (II) stress. This study provides a novel La(III)-based candidate for crop protection and furthers our understanding of rare earth element-induced mitigation of heavy metal stress.