The ZmCOP1s-ZmCOL3 Module Enhances Late Flowering, Grain Yield and Grain Quality in Maize

Area of Science:

• Plant Biology
• Genetics
• Agricultural Science

Background:

• Flowering time is crucial for crop yield and adaptation, primarily regulated by light signaling pathways.
• Arabidopsis CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1) is a key regulator of photomorphogenesis.

Purpose of the Study:

• To identify and characterize maize orthologs of COP1 (ZmCOP1a and ZmCOP1b) and elucidate their role in flowering time control and yield-related traits.

Main Methods:

• Identification of maize COP1 orthologs (ZmCOP1a, ZmCOP1b).
• Analysis of loss-of-function mutants and overexpression lines.
• Molecular interaction studies with ZmCOL3.
• Gene expression analysis of flowering regulators.
• Field trials to assess yield and grain quality.

Main Results:

• ZmCOP1a and ZmCOP1b activate light signaling, delay flowering, and reduce plant height.
• ZmCOP1s interact with ZmCOL3, upregulating flowering repressors and suppressing florigen genes.
• Overexpression of ZmCOP1s enhanced kernel number, size, and weight, while increasing protein and decreasing starch content.
• ZmCOL3 overexpression decreased both starch and protein content.

Conclusions:

• The ZmCOP1s-ZmCOL3 module is a critical regulator of flowering time and source-sink reallocation in maize.
• This module presents valuable genetic targets for breeding maize with improved yield, quality, and optimized flowering time.