Selenium Nanomaterials Enhance Sheath Blight Resistance and Nutritional Quality of Rice: Mechanisms of Action and Human Health Benefit

In the current work, the foliar application of selenium nanomaterials (Se⁰ NMs) suppressed sheath blight in rice (Oryza sativa). The beneficial effects were nanoscale specific and concentration dependent. Specifically, foliar amendment of 5 mg/L Se⁰ NMs decreased the disease severity by 68.8% in Rhizoctonia solani-infected rice; this level of control was 1.57- and 2.20-fold greater than that of the Se ions with equivalent Se mass and a commercially available pesticide (Thifluzamide). Mechanistically, (1) the controlled release ability of Se⁰ NMs enabled a wider safe concentration range and greater bioavailability to Se⁰ NMs, and (2) transcriptomic and metabolomic analyses demonstrated that Se⁰ NMs simultaneously promoted the salicylic acid- and jasmonic-acid-dependent acquired disease resistance pathways, antioxidative system, and flavonoid biosynthesis. Additionally, Se⁰ NMs improved rice yield by 31.1%, increased the nutritional quality by 6.4-7.2%, enhanced organic Se content by 44.8%, and decreased arsenic and cadmium contents by 38.7 and 42.1%, respectively, in grains as compared with infected controls. Human simulated gastrointestinal tract model results showed that the application of Se⁰ NMs enhanced the bioaccessibility of Se in grains by 22.0% and decreased the bioaccessibility of As and Cd in grains by 20.3 and 13.4%, respectively. These findings demonstrate that Se⁰ NMs can serve as an effective and sustainable strategy to increase food quality and security.