Physiological and molecular interventions for improving nitrogen-use efficiency in maize.

Abstract This chapter discusses (i) the importance of nitrogen in plant growth and development, (ii) what is nitrogen-use efficiency (NUE) and how to manage it, (iii) traits influencing nitrogen-uptake efficiency including root system architecture, root nitrogen transporter system, and interaction with microorganisms, (iv) traits influencing nitrogen-utilization efficiency, such as nitrate assimilation, canopy photosynthesis per unit of nitrogen, (v) identification and use of quantitative trait loci (QTLs) related to NUE, (vi) identification of nitrogen-responsive genes, and (vii) nitrogen signalling and transduction for improving NUE. Intensive research on molecular and genetic aspects of NUE has led to the identification of many new genes, QTLs and alleles that could be deployed to develop new genotypes. The future direction of the research efforts should be towards understanding the interaction of NUE-related genes with cellular small RNA flux and perturbing the system performance through metabolic engineering and genome editing techniques.