Abstract

Compact maize architecture is crucial for high planting densities and yields, which is a key breeding objective. In this study, a maize T-DNA insertion mutant with c ompact p lant a rchitecture ( cpa ) was identified, showing reduced leaf curling, drooping angle, plant and ear height, leaf dimensions, internode and tassel length, tassel branch number, and yield compared to WT. Paraffin section analysis showed reduced vein cross-sectional area, epidermal cell width, and increased vein density in the cpa mutant. Genetic analysis revealed that T-DNA was inserted into the first exon of a gene encoding TATA-box binding protein-associated factor (TAF) in the cpa mutant, which was named ZmTAF11 . ZmTAF11 exhibited ubiquitous expression across various tissues and nuclear localization. Loss-of-function Zmtaf11 mutants generated by CRISPR/Cas9 exhibited the characteristic compact phenotype, which was consistent with that of the cpa mutant. ZmTAF11 directly binds to the promoters of leaf morphogenesis-related genes ZmAXL and ZmBOB1 , thereby promoting their transcription. Furthermore, four SNPs in ZmTAF11 were significantly associated with ear height index (EHI), and the AGTG haplotype showed a lower EHI. This haplotype was predominantly found in temperate maize lines and geographically distributed across North America. These findings reveal the role of ZmTAF11 in regulating maize architecture and its potential application in high-density maize breeding.