Genome-Wide Identification and Analyses of the AHL Gene Family in Pepper (Capsicum annuum L.)

The AT-hook motif nuclear-localized (AHL) genes play crucial roles in chromatin remodeling and regulation of gene transcription, significantly influencing biological processes such as plant growth, development, and stress responses. Although AHL genes have been extensively studied in various plants, their biological roles in pepper (Capsicum annuum L.) remain unknown. In this study, 45 AHL genes were identified in the pepper genome through bioinformatics approaches. These genes were analyzed for their chromosomal distribution, phylogenetic relationships, and the structural and functional characteristics of their encoded proteins. Phylogenetic analysis categorized the CaAHL proteins into four subgroups. Transcriptome data revealed that CaAHL genes are expressed across various tissues, including roots, stems, flowers, seeds, and fruits, at different growth stages. Subcellular localization experiments confirmed that CaAHL23 predominantly localizes to the cell nucleus, consistent with the localization of its homolog TEK in Arabidopsis thaliana. A yeast two-hybrid assay revealed that CaAHL23 binds to the promoter of CaCYP703A2, which is the homolog of the genic male sterility gene SlCYP703A2 in tomato. These findings indicate a potential link between CaAHL23 and genic male fertility in pepper. In summary, this study provides valuable insights that establish a foundation for future functional studies of CaAHL genes in pepper.