The K and NO Interaction Mediated by NITRATE TRANSPORTER1.1 Ensures Better Plant Growth under K-Limiting Conditions.

K and NO are the major forms of potassium and nitrogen that are absorbed by the roots of most terrestrial plants. In this study, we observed that a close relationship between NO and K in Arabidopsis () is mediated by NITRATE TRANSPORTER1.1 (NRT1.1). The knockout mutants showed disturbed K uptake and root-to-shoot allocation, and were characterized by growth arrest under K-limiting conditions. The K uptake and root-to-shoot allocation of these mutants were partially recovered by expressing in the root epidermis-cortex and central vasculature using and promoters, respectively. Two-way analysis of variance based on the K contents in / , / , / , and / double mutants and the corresponding single mutants and wild-type plants revealed physiological interactions between NRT1.1 and K channels/transporters located in the root epidermis-cortex and central vasculature. Further study revealed that these K uptake-related interactions are dependent on an H-consuming mechanism associated with the H/NO symport mediated by NRT1.1. Collectively, these data indicate that patterns of NRT1.1 expression in the root epidermis-cortex and central vasculature are coordinated with K channels/transporters to improve K uptake and root-to-shoot allocation, respectively, which in turn ensures better growth under K-limiting conditions.