A C-terminal encoded peptide, ZmCEP1, is essential for kernel development in maize

Area of Science:

• Plant Biology
• Molecular Genetics
• Agricultural Science

Background:

• C-terminal encoded peptides (CEPs) are mobile peptide hormones regulating plant development.
• CEPs are known to influence growth and stress responses in Arabidopsis and rice.
• The function of CEPs, specifically ZmCEP1, in maize remains largely unexplored.

Purpose of the Study:

• To investigate the spatiotemporal expression and function of ZmCEP1 in maize.
• To elucidate the role of ZmCEP1 in regulating maize plant growth and kernel development.
• To identify molecular mechanisms underlying ZmCEP1's effects on maize.

Main Methods:

• Analysis of ZmCEP1 spatiotemporal expression patterns in maize.
• Heterologous expression and overexpression studies in Arabidopsis and maize.
• CRISPR/Cas9 gene editing to create ZmCEP1 knock-out mutants.
• Exogenous application of ZmCEP1 peptide.
• Transcriptome analysis of ZmCEP1 knock-out mutants.

Main Results:

• ZmCEP1 is highly expressed in young maize ears and tassels, particularly in vascular tissues.
• Overexpression of ZmCEP1 reduced plant size, ear characteristics, and kernel weight in maize.
• ZmCEP1 application inhibited root elongation in both Arabidopsis and maize.
• ZmCEP1 knock-out increased plant height, ear height, kernel size, and 100-kernel weight.
• ZmCEP1 knock-out led to upregulation of genes related to nitrogen metabolism, nitrate/sugar transport, and auxin response.

Conclusions:

• ZmCEP1 plays a crucial role in negatively regulating maize plant growth and kernel development.
• ZmCEP1 functions as an endogenous inhibitor of growth and development in maize.
• ZmCEP1 knock-out presents a promising avenue for enhancing maize yield and breeding.