Genetic and molecular mechanisms underlying nitrogen use efficiency in maize.

Nitrogen (N) is vital for crop growth and yield, impacting food quality. However, excessive use of N fertilizers leads to high agricultural costs and environmental challenges. This review offers a thorough synthesis of the genetic and molecular regulation of N uptake, assimilation, and remobilization in maize, emphasizing the role of key genes and metabolic pathways in enhancing N use efficiency (NUE). We summarize the genetic regulators of N transports for nitrate (NO₃^-) and ammonium (NH₄⁺) that contribute to efficient N uptake and transportation. We further discuss the molecular mechanisms by which root system development adapts to N distribution and how N influences root system development and growth. Given the advancements in high-throughput microbiome studies, we delve into the impact of rhizosphere microorganisms on NUE and the complex plant-microbe interactions that regulate maize NUE. Additionally, we conclude with intricate regulatory mechanisms of N assimilation and remobilization in maize, involving key enzymes, transcription factors and amino acid transporters. We also scrutinize the known N signaling perception and transduction mechanisms in maize. This review underscores the challenges in improving maize NUE and advocates for an integrative research approach that leverages genetic diversity and synthetic biology, paving the way for sustainable agriculture.