ZmGRAS11, transactivated by Opaque2, positively regulates kernel size in maize

Area of Science:

• Plant genetics and molecular biology
• Crop science
• Maize (Zea mays) research

Background:

• Endosperm development in maize is crucial for grain yield, but the coordination of grain filling with kernel size is not fully understood.
• Modern breeding has successfully increased maize kernel size, indicating underlying genetic mechanisms that are yet to be fully elucidated.

Purpose of the Study:

• To identify genetic factors regulating kernel size and weight in maize.
• To elucidate the molecular mechanism coordinating endosperm enlargement with grain filling in maize.

Main Methods:

• Comparative analysis of modern and historical maize varieties.
• Identification and characterization of novel transcriptional regulators.
• Gene expression analysis and protein-protein interaction studies.

Main Results:

• Increased kernel size has been a target of selection in modern maize breeding.
• A novel DELLA-like transcriptional regulator, ZmGRAS11, was identified and shown to positively regulate maize kernel size and weight.
• The transcription factor Opaque2 directly activates ZmGRAS11 expression, suggesting a regulatory module.

Conclusions:

• The Opaque2-ZmGRAS11 module plays a key role in mediating synergistic endosperm enlargement and grain filling in maize.
• Understanding this genetic pathway offers potential for improving maize yield through targeted breeding strategies.