European Journal of Sustainable Agroecosystems

Background: Nitrogen (N) is a fundamental macronutrient restricting global wheat (Triticum aestivum L.) productivity. Excessive nitrogenous fertilizer application leads to severe environmental degradation, while nitrogen deficiency dramatically lowers grain yield and quality. To develop nitrogen-use efficient (NUE) cultivars, deciphering the molecular mechanisms governing nutrient uptake under variable nitrogen regimes is paramount. High-throughput transcriptomics offers unprecedented resolution into the dynamic gene expression networks driving these responses.
Objective of the review: This comprehensive review synthesizes recent insights into the transcriptomic regulation of nitrogen uptake, assimilation, and transport systems in wheat. It evaluates how varying nitrogen levels modulate gene networks to remodel root architecture and metabolic pathways.
Sources of literature: A systematic search was executed across Scopus, Web of Science, PubMed, and Google Scholar for peer-reviewed studies published between 2015 and 2026 focusing on wheat transcriptomics, nitrogen stress, and nutrient transport.
Major findings: Transcriptomic profiling reveals that low-nitrogen stress triggers the upregulation of high-affinity transport systems (HATS), notably specific TaNRT2 variants and TaAMT ammonium transporters, coordinated by master transcription factor families (WRKY, NAC, bHLH, MYB). Conversely, high nitrogen environments downregulate HATS and induce low-affinity transport systems (LATS; TaNRT1/NPF). Cross-talk transcriptomics shows that nitrogen regimes tightly regulate secondary nutrient transporters (phosphorus, potassium, sulfur, and iron), highlighting a coordinated multi-nutrient homeostasis network.
Research gaps: Key gaps include a profound underrepresentation of spatial (cell-type specific) and temporal resolution in allopolyploid wheat transcriptomics, limited functional characterization of the vast majority of non-coding RNAs (lncRNAs, miRNAs), and a shortage of validated field-scale multi-omics integrations.
Conclusion: Understanding the transcriptomic landscape of wheat under variable nitrogen regimes bridges the gap between functional genomics and molecular breeding. Future directions must leverage single-cell RNA sequencing (scRNA-seq) and CRISPR-mediated network editing to engineer resilient, high-yielding, low-input wheat ideotypes.