Phosphorylation at Ser28 stabilizes the Arabidopsis nitrate transporter NRT2.1 in response to nitrate limitation

) failed to complement the growth-restricted phenotype of the nrt2.1 mutant when a low concentration of nitrate was the sole nitrogen source. These results demonstrate that phosphorylation at Ser28 is crucial for NRT2.1 protein stabilization and accumulation in response to nitrate limitation.