Enantioselective accumulation and translocation of cadmium and dinotefuran in rice (Oryza sativa L.) under co-exposure condition

Cd accumulation in rice exhibited enantioselectivity under Cd-DIN co-exposure. • S -DIN effectively reduced Cd bioavailability and root-to-grain translocation. • OsABCG14 mediated enantioselective Cd-DIN transport via differential binding. • OsABCG14 exhibited preferential binding to Cd- R -DIN over Cd- S -DIN. The interactions between heavy metals and chiral pesticides within agricultural ecosystems remain largely neglected, obscuring environmental behaviors. This study investigated the accumulation and translocation of cadmium (Cd) and chiral dinotefuran (DIN) in rice ( Oryza sativa L . ) under varying co-exposure conditions (hydroponics versus soil; foliar versus root exposure). Surprisingly, co-exposure exhibited a significant enantioselective effect on Cd accumulation. During the tillering stage, Cd- R -DIN caused slight differences in Cd accumulation within plant tissues compared to single Cd, whereas S -DIN markedly reduced Cd accumulation. At the grain-filling and maturity stages, co-exposure decreased the accumulation of both Cd (18.8 %–40.2 %) and DIN (22.3 %–63.3 %). Notably, Cd accumulation in grain under Cd- R -DIN (4.5 × 10 -3 mg/kg) was 3-fold higher than under Cd- S -DIN (1.5 × 10 -3 mg/kg), aligning with a 1.58-fold higher R -DIN accumulation. This indicated that standard doses of DIN (0.06 kg active ingredient/hectare), particularly S -DIN, mitigated Cd bioavailability and root-to-grain translocation. Spectroscopic analyses excluded the enantioselective possibility of direct chemical complexation between DIN and Cd. Proteomics identified ABC transporters as key regulators, with OsABCG14 being upregulated (17.6 %) by Cd- R -DIN but downregulated (18.4 %) by Cd- S -DIN. Molecular dynamics simulations revealed that OsABCG14 exhibited a more favorable binding ability with Cd- R -DIN (−60.1 kJ/mol) than with Cd- S -DIN (−43.5 kJ/mol). Heterologous expression in yeast confirmed that strains overexpressing OsABCG14 exhibited increased sensitivity to Cd- R -DIN, validating enantioselective transport. These findings highlight that the targeted application of specific pesticide enantiomers (e.g., S -DIN) could serve as a dual-action strategy for pest management and heavy metal mitigation in co-contaminated agricultural environments. Download: Download high-res image (274KB) Download: Download full-size image