ERECTA genes and their ligands regulate shoot and inflorescence architecture in maize.

Abstract

In maize, several yield-related traits are associated with meristem activity, regulated by CLAVATA3/EMBRYO SURROUNDING REGION-related (CLE) peptide signals perceived by CLAVATA(CLV) receptors in the CLAVATA-WUSCHEL (CLV-WUS) pathway. However, additional signaling pathways in maize meristem development remain poorly understood. Here, we identify three receptor-like kinases, ZmERECTA1 (ZmER1), ZmER2 and ZmER1-like (ZmERL), and their ligands, EPIDERMAL PATTERNING FACTOR-like (ZmEPFL), as critical regulators of meristem activity, plant architecture, and ear development. We demonstrate that ZmER receptors act redundantly, with ZmER1 playing a primary role. Zmer1 mutants have compact architecture, enlarged inflorescence meristems (IMs), and increased kernel row numbers (KRNs), while higher-order Zmer mutants display exacerbated phenotypes. We further reveal that ZmER1 specifically binds to five EPFL peptides, which act redundantly in ear development regulation. Furthermore, we find that ZmWUS1 is upregulated in Zmer mutants and mutation in Zmwus1 partially suppress the enlarged IM of Zmer1 mutants. We also generate weak Zmer1 alleles with enhanced yield traits, including reduced leaf angles and increased KRN. These findings offer valuable insights into ER-EPFL signaling in maize meristem development and provide promising genetic targets for breeding high-yield maize varieties through optimized plant and ear architecture.