The dual-affinity nitrate transceptor NITRATE TRANSPORTER1.1 (NRT1.1) has two modes of transport and signaling, governed by Thr-101 (T101) phosphorylation. NRT1.1 regulates lateral root (LR) development by modulating nitrate-dependent basipetal auxin export and nitrate-mediated signal transduction. Here, using the Arabidopsis (Arabidopsis thaliana) NRT1.1T101D phosphomimetic and NRT1.1T101A nonphosphorylatable mutants, we found that the phosphorylation state of NRT1.1 plays a key role in NRT1.1 function during LR development. Single-particle tracking revealed that phosphorylation affected NRT1.1 spatiotemporal dynamics. The phosphomimetic NRT1.1T101D form showed fast lateral mobility and membrane partitioning that facilitated auxin flux under low-nitrate conditions. By contrast, nonphosphorylatable NRT1.1T101A showed low lateral mobility and oligomerized at the plasma membrane (PM), where it induced endocytosis via the clathrin-mediated endocytosis and microdomain-mediated endocytosis pathways under high-nitrate conditions. These behaviors promoted LR development by suppressing NRT1.1-controlled auxin transport on the PM and stimulating Ca2+-ARABIDOPSIS NITRATE REGULATED1 signaling from the endosome.

• MeSH
• Arabidopsis genetics   growth & development   metabolism   MeSH
• Nitrates metabolism   MeSH
• Phosphorylation MeSH
• Plant Roots growth & development   MeSH
• Indoleacetic Acids metabolism   MeSH
• Arabidopsis Proteins metabolism   MeSH
• Anion Transport Proteins genetics   metabolism   MeSH
• Plant Proteins genetics   metabolism   MeSH
• Transcription Factors metabolism   MeSH
• Calcium Signaling MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• ANR1 protein, Arabidopsis MeSH Browser
• Nitrates MeSH
• Indoleacetic Acids MeSH
• NRT1.1 protein, Arabidopsis MeSH Browser
• Arabidopsis Proteins MeSH
• Anion Transport Proteins MeSH
• Plant Proteins MeSH
• Transcription Factors MeSH