Multi-Omics Analysis of the Maize Ear Diameter Mutant3 (Zmed3) Provides Insights into Female Inflorescence Development

Abstract

Ear is a crucial component of final yield in maize. Understanding how ear is developed is essential for maize genetic improvement and molecular breeding. Here, we analyzed the ZmED3 mutant, which shows flattened ear tip and disordered kernel rows, is a single recessive mutation isolated from the Lx9801 breeding population. Using integrated transcriptomic, proteomic, and metabolomic analyses at the 4 mm stage of developing ears, we identified 1,589 differentially expressed genes (DEGs), 185 differentially accumulated proteins (DAPs), and 122 differentially accumulated metabolites (DAMs) in ZmED3 mutants compared with normal siblings. These global omics changes were primarily associated with central carbon metabolism. Mutant ZmED3 inflorescence meristems (IMs) were initially enlarged, switched to a more fasciated pattern, and finally leading to impaired spikelet meristems (SMs). Transcriptomics suggested activation of the jasmonic acid signaling pathway, potentially affecting spikelet cell elongation. Proteomics indicated disruption of the MAPK signaling pathway, likely affecting spikelet cell polarity. Metabolomics demonstrated deficiencies in the tricarboxylic acid cycle and phenylpropanoid synthesis pathway, which in turn alter meristem cells differentiation and cell wall remodeling. Multi-omics integration uncovered a regulatory network involving cell cycle initiation, jasmonic acid signaling, and metabolic flux homeostasis, and pinpointed several candidate genes for future functional characterization. Our study not only suggests potential mechanism for maize ear development, but also provides possible targets for maize genetic improvement.

Keywords: maize ear, transcriptome, proteome, metabolome, candidate genes