Abstract: The AINTEGUMENTA (ANT) transcription factor family plays important roles in floral organogenesis and plant development; however, the mechanisms by which ANT proteins regulate yield remain unclear. Here, we conducted a genome-wide search and identified 64 ANT genes in the wheat genome. Association analysis of yield-related traits in 403 wheat accessions revealed that ANT family genes were significantly associated with grain size and weight. Among these genes, TaANT11-4A showed a strong association with yield-related traits. Three single-nucleotide polymorphisms (SNPs) near TaANT11-4A modulated its expression and defined two haplotypes. TaANT11-4A^Hap2 was identified as an elite allele associated with increased grain size. Overexpression of TaANT11-4A significantly increased grain size and overall plant biomass, largely owing to higher photosynthetic rates and increased activities of key enzymes involved in photosynthesis and carbohydrate metabolism in the transgenic plants. Further analyses demonstrated that TaANT11-4A directly binds to and activates TaEGY2, TaAAE1, and TaAAE2, which are involved in photosynthesis and carbohydrate metabolism. Consistent with these findings, knockout of TaEGY2 reduced grain size and yield, whereas overexpression of TaEGY2 or TaAAE2 increased these traits relative to the wild type (WT). Collectively, our results demonstrate that TaANT family proteins, particularly TaANT11-4A, are key regulators of wheat grain size and yield through the direct transcriptional activation of genes that coordinate photosynthesis and carbohydrate metabolism.

Key words: biomass, carbohydrate metabolism, grain size, photosynthesis, TaANT11-4A, wheat