The transcription factor ZmNLP5 increases maize grain yield by regulating nitrogen assimilation genes

Nitrogen (N) is crucial for maize ( Zea mays L.) growth, development and yield. Dysfunction of the maize NIN-like protein 5 (ZmNLP5) reduces N assimilation, but the precise mechanism by which ZmNLP5 modulates N metabolism and its contribution to agricultural applications are not well understood. In this study, our transcriptomic profiling and chromatin immunoprecipitation followed by sequencing (ChIP-seq) analyses reveal 581 ZmNLP5-modulated target genes. We confirmed that ZmNLP5 physically interacted and transactivated contributors to N assimilation, including ZmNRT1.1D , ZmNIR1.1 , ZmNR2.1 , ZmGS4, ZmAS1 , and ZmLBD6 . Overexpression of ZmNLP5 upregulated N metabolism genes, and enhanced the enzymatic activities of nitrate reductase and glutamine synthase. Furthermore, overexpressing ZmNLP5 increased grain yield under both normal-N and low-N conditions. Introgression of the overexpressed ZmNLP5 allele into Zhengdan 958 resulted in comparable yield increases in field trials. Our study unveiled that ZmNLP5 is a potential genetic target for increasing nitrogen use efficiency and grain yield in maize.