Amine ester improves rice growth and resistance by promoting ammonium and potassium uptake

Fertilizers play a crucial role in improving crop yields; however, excessive fertilizer application leads to environmental pollution, increases greenhouse gas emissions, and contributes to global warming. Therefore, improving fertilizer efficiency is of great significance for crop production and ecological security. Octanoic acid (OA), a type of straight-chain saturated fatty acid commonly found in plants and animals, is known to promote plant growth. In this study, we synthesized amine esters (AE) using OA as the precursor. AE demonstrated a greater growth-promoting effect than OA. To further explore the mechanism underlying AE-induced growth promotion, the responses of macro-element transporter mutants to AE were analyzed. Genetic and physiological studies indicated that mutants of potassium channel AKT1 and ammonium transporter 1 (AMT1) inhibited AE-induced growth promotion in rice seedlings, whereas mutants of nitrate transporter 1.1B (NRT1.1B) and phosphate transporter 8 (PT8) did not significantly inhibit AE-induced growth. Additionally, yeast rescue assays revealed that AE significantly enhanced the absorption of ammonium and potassium ions. Glutamine synthetase 1 (gs1;1) mutants exhibited a response similar to that of AMT1 RNAi, which inhibited AE-induced growth promotion. Furthermore, the administration of AE led to increased chlorophyll accumulation and enhanced resistance to rice blast and sheath blight (ShB) via the potassium and ammonium pathways, respectively. AE also improved tolerance to saline and saline-alkaline stresses through these pathways. In conclusion, AE represents a novel fertilizer additive that promotes rice growth and enhances tolerance to biotic and abiotic stresses by activating ammonium and potassium uptake.