Abstract: Nitrogen (N) is an essential macronutrient for plants and profoundly affects crop yields and qualities. Ammonium (NH₄⁺+) and nitrate (NO₃^?) are major inorganic N forms absorbed by plants from the surrounding environments. Intriguingly, NH₄⁺+ 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 NH₄⁺ and the alleviation of NH₄⁺+ toxicity. To fully decipher the molecular mechanisms underlying how plants minimize NH₄⁺+ toxicity may broadly benefit agricultural practice. In the current minireview, we attempt to discuss recent discoveries in the strategies for mitigating NH₄⁺+ toxicity in plants, which may provide potential solutions for improving the nitrogen use efficiency (NUE) and stress adaptions in crops.

Key words: alleviation, ammonium toxicity, channel, nitrogen, NUE, transporter