NITROGEN RESPONSE DEFICIENCY 1-mediatedCHL1induction contributes to optimized growth performance during altered nitrate availability inArabidopsis

Abstract

Plants cannot fix nitrogen directly; they must absorb it from the soil through their roots, or in rare cases, form associations with nitrogen-fixing bacteria. The efficiency of nitrogen use in most domesticated crops is low, and more than half of the available nitrogen in the soil can leach into the environment. Understanding the nitrogen signaling pathways is essential for maximizing the efficiency of nitrogen use in crops. In the present study, we characterized theMyeloblastosis(Myb)-like geneNITROGEN RESPONSE DEFICIENCY 1(NID1). We observed that the growth performance ofnid1knockout (KO) mutant Arabidopsis plants was better than that of wild-type Col-0 plants under very low-nitrate conditions, leading to improved growth performance in thenid1KO plants. The results of chromatin immunoprecipitation and electrophoretic mobility shift assays indicated that NID1 binds to the promoter of theNITRATE TRANSPORTER(NRT)1.1gene. Furthermore,nid1KO plants exhibited similar growth performance to thenid1KO/chl1-5(nrt1.1KO) double mutant andchl1-5(nrt1.1KO) plants in response to low-nitrate conditions. We suggest that NID1 plays a crucial role as a transcription factor in optimizing plant growth by modulating the transcript abundance of the nitrate transceptorCHL1, leading to enhanced ABA accumulation in low-nitrate conditions.