The Mechanism of Manganese Ferrite Nanomaterials Promoting Drought Resistance in Rice

Strategies to reduce the risk of drought damage are urgently needed as intensified climate change threatens agricultural production. One potential strategy was using nanomaterials (NMs) to enhance plant resistance by regulating various physiological and biochemical processes. In the present study, 10 mg kg(-1) manganese ferrite (MnFe2O4) NMs had the optimal enhancement to elevate the levels of biomass, photosynthesis, nutrient elements, and polysaccharide in rice by 10.9-525.0%, respectively, under drought stress. The MnFe2O4 NMs were internalized by rice plants, which provided the possibility for rice to better cope with drought. Furthermore, as compared with drought control and equivalent ion control, the introduction of MnFe2O4 NMs into the roots significantly upregulated the drought-sensing gene CLE25 (29.4%) and the receptor gene NCED3 (59.9%). This activation stimulated downstream abscisic acid, proline, malondialdehyde, and wax biosynthesis by 23.3%, 38.9%, 7.2%, and 26.2%, respectively. In addition, 10 mg.kg(-1) MnFe2O4 NMs significantly upregulated the relative expressions of OR1, AUX2, AUX3, PIN1a, and PIN2, and increased IAA content significantly, resulting in an enlarged root angle and a deeper and denser root to help the plant withstand drought stresses. The nutritional quality of rice grains was also improved. Our study provides crucial insight for developing nano-enabled strategies to improve crop productivity and resilience to climate change.

Automated summary

Strategies to reduce drought damage in agriculture are urgently needed due to intensified climate change. The use of nanomaterials (NMs) to enhance plant resistance has shown promising results. In this study, the addition of 10 mg kg(-1) manganese ferrite (MnFe2O4) NMs significantly improved rice biomass, photosynthesis, nutrient elements, and polysaccharide levels under drought stress. The internalization of MnFe2O4 NMs by rice plants contributed to their ability to cope with drought. Furthermore, the introduction of MnFe2O4 NMs upregulated drought-sensing and receptor genes in the roots, leading to the synthesis of important compounds that helped plants withstand drought stresses and improved the nutritional quality of rice grains. This study provides valuable insights for developing nano-enabled strategies to enhance crop productivity and resilience against climate change.