Transcriptional corepressors in maize maintain meristem development

Area of Science:

• Plant developmental biology
• Genetics and genomics
• Crop science

Background:

• Plant body formation relies on postembryonic meristems, requiring precise regulation for development and yield.
• The RAMOSA1 ENHANCER LOCUS2 (REL2) gene family in maize encodes transcriptional corepressors crucial for meristem regulation.

Purpose of the Study:

• To investigate the cooperative function of REL2 and RELK1 in maize ear inflorescence meristem (IM) development.
• To explore the potential of manipulating the REL2 gene family for enhancing crop yield.

Main Methods:

• Genetic screening to identify mutations affecting meristem development.
• Expression and genetic analyses to understand gene interactions.
• Phenotypic analysis of maize mutants and hybrids to assess meristem size and kernel formation.

Main Results:

• Mutations in RELK1, identified as a rel2 enhancer, led to enlarged ear IMs.
• REL2 and RELK1 cooperatively regulate ear IM development by influencing redox balance, hormone homeostasis, and differentiation.
• RELK genes exhibit redundant yet diverse roles in maintaining various meristem types.
• Subtle increases in ear IM size in rel2 heterozygous plants resulted in extra kernel rows across diverse hybrids.

Conclusions:

• The REL2 gene family is essential for plant development from embryogenesis to reproduction.
• REL2 and RELK1 interaction is critical for ear IM development and stem cell maintenance via ZmWUSCHEL1.
• Targeting the REL2 family offers a promising strategy for improving seed yield in maize.