Pesticide-fertilizer interactions: nutrient effects on wheat detoxification of prothioconazole.

BACKGROUND Prothioconazole (PTC), a triazole fungicide, and its metabolite prothioconazole-desthio (dPTC) present potential phytotoxic risks in crops. However, the mechanisms governing their uptake and detoxification in wheat remain unknown. This study aimed to determine how macronutrients and endogenous signaling compounds regulate PTC absorption and metabolism in wheat seedlings. RESULTS High potassium availability markedly enhanced PTC uptake, resulting in a > 600% increase in PTC uptake over 12 h compared to the low potassium. Exogenous application of indole-3-acetic acid and brassinolide led to significant increases in PTC accumulation by 121.7% and 94.4%, respectively. Transcriptomic analysis revealed that PTC activated detoxification pathways, with prominent up-regulation of adenosine triphosphate (ATP)-binding cassette transporters and mitogen-activated protein kinase (MAPK) signaling components. Under nitrogen-deficient conditions, 1493 genes were specifically down-regulated, including those related to ribosome biogenesis, phenylalanine metabolism, and membrane transport, indicating a reduced detoxification capacity and enhanced dPTC retention. CONCLUSION Nitrogen availability plays a pivotal role in modulating the molecular response of wheat to PTC exposure. Nitrogen deficiency markedly down-regulated key genes involved in detoxification processes, thereby aggravating PTC-induced phytotoxicity. These results underscore the critical interplay between nutrient status and pesticide metabolism, providing mechanistic evidence to inform integrated pesticide-fertilizer management strategies aimed at minimizing chemical residues in food crops and enhancing agroecosystem sustainability. © 2025 Society of Chemical Industry.