Interactions of molybdenum disulfide nanosheets with wheat plants under changing environments: More than meets the eye?

Molybdenum disulfide (MoS₂) nanosheets are being increasingly employed in various applications. It is therefore imperative to assess their potential environmental implications in a changing world, particularly in the context of global warming. Here, we assessed the effects of MoS₂ nanosheets on wheat Triticum aestivum L. under today's typical climatic conditions (22 °C) and future climatic conditions (30 °C), respectively. The results showed that MoS₂ nanosheets (10 and 100 Mo mg/L) did not significantly affect wheat plant growth, root morphological traits, and chlorophyll fluorescence, regardless of dose and temperature. However, the metabolic processes were significantly altered in T. aestivum upon exposure to individual MoS₂ nanosheets and to a combination of MoS₂ nanosheets and future global warming. As a non-specific protective strategy, the wheat plants that were under stress conditions maintained the stability of cell membranes and thus relieved cell injury by accumulating more glycerophospholipids. Warming additionally influenced the nitrogen and carbon pool reallocation in wheat root. MoS₂ nanosheets mainly depleted a range of antioxidant metabolites involved in phenylpropanoid biosynthesis and taurine and hypotaurine metabolism, while warming activated vitamin B6 cofactors related to vitamin B6 metabolism. Metabolites involved in glutathione metabolism were uniquely upregulated while most metabolites associated with nucleotide metabolisms were uniquely downregulated in combination-treated wheat. Overall, wheat plants regulated a wide range of growth-related processes, including carbohydrate, amino acids, lipid, vitamins, and nucleotide metabolism, to maintain optimal metabolite pool sizes and eventually global metabolic homeostasis upon different stress conditions. Our findings provide novel insights into MoS₂ nanosheets-mediated crop responses under global warming.