Genome-Wide Dissection of the Dof Transcription Factor Family in Senna tora: From Gene Identification to Expression Signatures

Dof (DNA binding with one finger) transcription factors constitute a plant-specific family of transcriptional regulators that play extensive roles in plant growth, development, and secondary metabolism. However, a systematic identification and evolutionary analysis of the Dof gene family in the medicinal plant Senna tora (S. tora) has not yet been reported. In this study, a genome-wide identification and phylogenetic analysis of the Dof gene family in S. tora was performed to elucidate its evolutionary patterns and potential functions. The results revealed a total of 36 StDof genes in the S. tora genome, which were classified into four subfamilies, with subgroup D representing the largest proportion. Collinearity analysis further revealed the evolutionary history of the StDof gene family, identifying 23 gene pairs, with Ka/Ks values for all homologous gene pairs being less than 1. It was also found that StDof promoters contain a large number of regulatory elements associated with hormone responses, light signaling, and various abiotic stresses. Furthermore, the expression profiles of StDof genes at seven different developmental stages of the seed demonstrated that 18 genes were preferentially expressed in early development, whereas 18 genes were preferentially expressed in late development. The differentially expressed genes, StDof9 (upregulated) and StDof16 (downregulated), were successfully identified. Subcellular localization experiments confirmed that the candidate genes StDof9 and StDof16 exert their biological functions within the nucleus, consistent with the prediction results. Taken together, this study provides a theoretical foundation for understanding the evolutionary history of the Dof gene family in S. tora and lays the groundwork for future functional characterization of StDof genes.