ZmNPF7.10 confers potassium and nitrogen distribution from node to leaf in maize

Area of Science:

• Plant Biology
• Molecular Biology
• Agricultural Science

Background:

• Nodes in graminaceous plants are crucial for nutrient allocation, particularly to developing leaves and reproductive organs.
• The molecular mechanisms governing nutrient distribution in plant nodes are not well understood.

Purpose of the Study:

• To identify and characterize transporters involved in potassium (K) and nitrogen (N) distribution within maize nodes.
• To elucidate the molecular mechanisms of nutrient transport in maize.

Main Methods:

• Functional characterization of ZmNPF7.10 in Xenopus oocytes.
• Analysis of ZmNPF7.10 expression patterns in maize tissues.
• Phenotypic analysis of ZmNPF7.10 disruption mutants.
• Association analysis of a natural promoter variant with transcript levels and physiological traits.

Main Results:

• ZmNPF7.10 exhibits nitrate (NO3-) and potassium (K+) transport activity in a pH-dependent manner.
• ZmNPF7.10 is primarily expressed in maize nodes during the reproductive stage, specifically in xylem parenchyma cells of enlarged vascular bundles (EVBs).
• Disruption of ZmNPF7.10 leads to reduced K and N in leaves and accumulation in nodes, indicating its role in node-to-leaf nutrient transport.
• A natural 7.1-kb InDel variant in the ZmNPF7.10 promoter is associated with transcript levels, leaf nutrient concentration, and grain yield.

Conclusions:

• ZmNPF7.10 acts as a dual-function transporter mediating K and N distribution in maize nodes.
• This transporter plays a significant role in nutrient allocation from nodes to leaves, influencing overall plant nutrition and yield.
• The identified promoter variant offers potential for marker-assisted selection to improve maize yield.