WRKY46 promotes ammonium tolerance in Arabidopsis by repressing NUDX9 and indole?3?acetic acid?conjugating genes and by inhibiting ammonium efflux in the root elongation zone

Ammonium (NH4+) is toxic to root growth in most plants, even at moderate concentrations. Transcriptional regulation one of the important mechanisms response plants NH4+ toxicity, but nature involvement transcription factors (TFs) this remains unclear. Here, RNA-seq analysis was performed on Arabidopsis roots screen for ammonium-responsive TFs. WRKY46, member WRKY factor family responsive NH4+, selected. We defined role WRKY46 using mutation and overexpression assays, characterized NUDX9 indole-3-acetic acid (IAA)-conjugating genes by via yeast one-hybrid electrophoretic mobility shift assays chromatin immunoprecipitation-quantitative real-time polymerase chain reaction (ChIP-qPCR). Knockout increased, while decreased, NH4+-suppression primary root. shown directly bind promoters IAA-conjugating (GH3.1, GH3.6, UGT75D1, UGT84B2) inhibit their transcription, thus positively regulating free IAA content stabilizing protein N-glycosylation, leading an inhibition efflux elongation zone (EZ). identify TF EZ, show that inhibits negative genes.