A nitrate transporter encoded by ZmNPF7.9 is essential for maize seed development

Area of Science:

• Plant Biology
• Molecular Genetics
• Agricultural Science

Background:

• Nitrogen, particularly nitrate, is vital for plant growth.
• The precise role of nitrate transport in maize seed development remains unclear.

Purpose of the Study:

• To investigate the function of the maize nitrate transporter ZmNPF7.9 (NRT1.5) in seed development and grain weight.

Main Methods:

• Identification and characterization of the maize mutant zmnpf7.9.
• Gene expression analysis in maize endosperm.
• Functional analysis using cRNA-injected Xenopus oocytes.
• Analysis of metabolic gene expression in the mutant.

Main Results:

• ZmNPF7.9 is specifically expressed in the basal endosperm transfer layer.
• Mutant zmnpf7.9 exhibits delayed endosperm development, abnormal starch, and reduced grain weight.
• ZmNPF7.9 functions as a pH-dependent bidirectional nitrate transporter.
• Nitrate levels and key metabolic gene expression are reduced in the mutant seeds.

Conclusions:

• ZmNPF7.9 is essential for nitrate delivery to the developing maize endosperm.
• This transporter regulates seed development and grain weight by influencing nutrient transport and metabolism.
• Findings offer insights for maize genetic improvement.