The alleviation of ammonium toxicity in plants

Abstract Nitrogen (N) is an essential macronutrient for plants and profoundly affects crop yields and qualities. Ammonium (NH 4 + ) and nitrate (NO 3 − ) are major inorganic N forms absorbed by plants from the surrounding environments. Intriguingly, NH 4 + is usually toxic to plants when it serves as the sole or dominant N source. It is thus important for plants to coordinate the utilization of NH 4 + and the alleviation of NH 4 + toxicity. To fully decipher the molecular mechanisms underlying how plants minimize NH 4 + toxicity may broadly benefit agricultural practice. In the current minireview, we attempt to discuss recent discoveries in the strategies for mitigating NH 4 + toxicity in plants, which may provide potential solutions for improving the nitrogen use efficiency (NUE) and stress adaptions in crops.