Comprehensive Characterization of the FATs Gene Family in Maize: Phylogeny, Expression Patterns, and Regulatory Networks

Background: Fatty acyl–ACP thioesterase (FAT) genes regulate fatty acid composition and content, yet the FAT family in maize has not been systematically characterized. Methods: Ten ZmFAT genes were identified from the maize genome and analyzed for gene structure, protein properties, phylogeny, collinearity, cis-acting elements, and predicted interactions. Transcriptome and qRT–PCR data were used to assess expression patterns during seed development. Results: The ten ZmFAT genes were grouped into two subfamilies (three ZmFATA and seven ZmFATB genes). Two pairs of collinear genes were detected within maize and one pair between maize and rice. Promoter analysis revealed light- and development-responsive elements. Two genes were functionally annotated in fatty acid biosynthesis, while five proteins exhibited interactions and 14 miRNAs were predicted to regulate ZmFAT genes. Expression analysis showed that ZmFATA1/2 and ZmFATB4/6/7 maintained high expression in both upper and lower seed parts, and qRT–PCR confirmed their gradual upregulation during seed development. Conclusion: This study provides the first comprehensive characterization of the maize ZmFAT family, offering insights into fatty acid metabolism and valuable genetic resources for improving maize oil composition.