Enantiomer-Dependent Modulation of Lithium Uptake and Accumulation in Plants by Foliar Application of Chiral SeNPs

Abstract

The rapid expansion of lithium-based new energy technologies has led to substantial lithium inputs into soil, potentially threatening human health through the consumption of lithium-accumulated agricultural products. Therefore, efficient strategies are urgently needed to mitigate the uptake and accumulation of lithium in plant fruits. Nanotechnology offers promising avenues for enhancing stress resilience and improving the quality of crops grown in contaminated soils. Here, we found that lithium was distributed unevenly among tissues (leaves: 1365, roots: 508, stems: 112, and fruits: 24 mg kg–1) of eggplants grown in lithium-contaminated soil. Notably, foliar spraying of selenium nanoparticles with levorotatory chirality (l-SeNPs) effectively reduced fruit lithium content and promoted its accumulation in the leaves, roots, and stems, in which vacuolar compartmentalization was the primary pathway for tolerance to high lithium content, whereas the dextrorotatory enantiomer showed no such effects. Mechanism investigation elucidated that l-SeNPs can reinforce antioxidant defense systems of eggplant under lithium stress through a microbiome–metabolome–transcriptome bridging cascade, in which l-SeNPs substantially affected rhizosphere bacterial and metabolic networks along with minor changes in the bioavailability of lithium in rhizosphere soil. This study sheds light on the superiority of nanoscale chirality in modulating lithium uptake and accumulation in plants grown in metal-contaminated soil, providing strategies for agromining of lithium.