A reevaluation of the contribution of NRT NRT 1.1 to nitrate uptake in Arabidopsis Arabidopsis under low‐nitrate supply

摘要

NRT 1.1 has been previously characterized as a dual‐affinity nitrate transporter in Arabidopsis , though several lines of evidence have raised questions regarding its high‐affinity function in nitrate uptake. Here, we show that the induction of NRT 2.1‐ and NRT 2.2‐mediated nitrate uptake interferes with measurements of the contribution of NRT 1.1 to high‐affinity uptake using nrt1.1 mutants. Therefore, a nrt1.1/2.1/2.2 triple mutant was generated to reevaluate the role of NRT 1.1 in high‐affinity nitrate uptake. This triple mutant has a lower rate of nitrate uptake than the nrt2.1/2.2 double mutant under low external nitrate supply, resulting in a lower growth rate than that of the double mutant. Therefore, we conclude that NRT 1.1‐mediated high‐affinity nitrate uptake is necessary for plant growth under low‐nitrate conditions.