A genetic module boosts grain yield and nitrogen use efficiency by improving nitrate transport in maize

Area of Science:

• Agricultural Science
• Plant Biology
• Genetics

Background:

• Excessive nitrogen fertilizer application reduces crop nitrogen use efficiency (NUE) and causes environmental issues.
• Improving NUE is critical for sustainable agriculture and reducing fertilizer dependency.

Purpose of the Study:

• Identify genetic factors controlling nitrate concentration in maize root xylem.
• Uncover mechanisms to enhance maize nitrogen uptake and utilization for improved yield and sustainability.

Main Methods:

• Genome-wide association study (GWAS) to identify genetic loci related to nitrate concentration.
• Analysis of gene expression and protein function for identified candidate genes.
• Investigating the regulatory role of NCR1 and its downstream targets in nitrogen translocation.

Main Results:

• A novel locus, NCR1 (Nitrate Concentration Regulator 1), was identified, correlating with root xylem nitrate levels.
• NCR1 encodes a MYB transcription factor regulating the nitrate transporter NRT2.3, controlling root-to-shoot nitrate translocation.
• A specific allele (NCR1^-In) with a promoter deletion was found to decrease in frequency with increased fertilizer use; its introgression or NCR1/NRT2.3 overexpression boosted grain yield and nitrogen content.

Conclusions:

• The NCR1-NRT2.3 module is a crucial genetic component for regulating nitrate translocation in maize.
• This genetic module offers a promising target for breeding programs aimed at enhancing crop yield and nitrogen use efficiency.
• Understanding and manipulating NCR1 provides a strategy for developing more sustainable agricultural practices.