On the roots of nitrogen uptake

Abstract

On the roots of nitrogen uptake Roots are equipped with delicate nutrient uptake systems, which respond to systemic signals of nutrient demand, monitor the composition of the soil and coordinate the activities of specific nutrient transporters at the plasma membrane of root cells (Krapp et al., 2014). Nitrogen (N) is an essential macronutrient, which is commonly present as nitrate (NO 3 À) in well-aerated soils and one of the key limiting factors for plant growth and productivity. Nitrogen is therefore prevalent in fertilizers that are heavily applied in modern agriculture, and increasing interest to improve the understanding of plant nutrition promises to mitigate the associated environmental impacts. To improve N-use efficiency in crops, an important question to resolve is how NO 3 À uptake is regulated to ensure nutritional balance in the entire plant. In this issue of New Phytologist, Jacquot et al. (2020; pp. 1038-1054) report a new molecular mechanism, where phosphorylation of the NO 3 À transporter NRT2.1 on a C-terminal serine residue regulates NO 3 À uptake in the model plant Arabidopsis thaliana. These mechanistic insights open a new window for understanding nutrient acquisition in plants.