Manganese (II) sulfate mitigates cadmium and arsenic accumulation and toxicity in rice (Oryza sativa L.): Insights from multi-omics regulation mechanisms.

The distinct chemical behaviors of Cadmium (Cd) and arsenic (As) make the co-contaminated paddy soils pose severe risks to rice safety and public health. This study first demonstrates the manganese(II) sulfate (MnSO4) mitigates Cd and As co-accumulation and co-toxicity in rice, and elucidates the underlying mechanisms by employing integrated ionomic, transcriptomic and metabolomic analyses. Application of moderate to high doses of MnSO4 in pot experiments increased brown rice yield by 208.78-428.60% while reducing Cd and As content by 4.89-21.98% and 60.65-81.73%, respectively. MnSO4 mediates Cd distribution through direct competitive antagonism, whereas As sequestration is governed by more complex and indirect regulatory pathways. The MnSO4 amendment also orchestrates a remodeling of the mineral element network by regulating key genes and metal transporters. This mechanism ultimately limits the accumulation of Cd and As in the grain via distinct pathways: by hindering root to brown rice Cd translocation and inhibiting stem/leaf to brown rice As translocation. Transcriptomic and metabolomic analysis further revealed that Mn alleviates combined Cd-As stress by downregulating key pathways involved in lipid peroxidation and sphingolipid metabolism, thereby enhancing cellular membrane stability. Collectively, MnSO4 integrates transporter regulation, ionomic reconfiguration, and metabolic adaptation to alleviate Cd-As co-stress in rice. Our findings provide a effective approach to ensure rice safety in contaminated regions.