Genome-Wide Identification and Functional Characterization of the Dof Family in Dendrobium officinale

The Dof gene family represents a class of plant-specific transcription factors that play crucial regulatory roles in various biological processes, including plant growth, development, and responses to abiotic stress. However, genome-wide identification and functional characterization of the Dof gene family remain unexplored in <i>Dendrobium officinale</i>. In this study, we performed a genome-wide identification and functional analysis of the DoDof gene family. A total of 28 Dof family members were identified and named <i>DoDof1-28</i> based on genome annotation data. Phylogenetic analysis classified these genes into four major groups (A-D) and further subdivided them into nine subfamilies. Gene structure analysis revealed that most <i>DoDofs</i> lack introns, with no distinct specificity observed among different subfamilies and considerable diversity within the same subfamily. Sequence alignment analysis demonstrated that all DoDof proteins contain a conserved Dof domain consisting of 52 amino acids, which includes a C2-C2 zinc finger motif and a DNA-binding domain. MEME analysis revealed that the conserved motif composition exhibits a certain degree of conservation among DoDof proteins, but significant differences exist across subfamilies. Expression pattern analysis demonstrated that <i>DoDofs</i> have exhibited diverse expression profiles across different developmental stages, tissues, and under abiotic stresses (such as low temperature, salinity, and drought) in <i>D. officinale</i>, suggesting their potential roles in plant development and stress responses. Subcellular localization analysis indicated that DoDof15, DoDof22, and DoDof24 are localized exclusively in the nucleus. Yeast one-hybrid assays revealed that DoDof22 binds to the promoter of the ABA receptor <i>DoPYL9</i>, while DoDof15 and DoDof24 bind to the promoter of the bHLH transcription factor <i>DobHLH68</i>. These results suggest that DoDof proteins may regulate the growth, development, and stress response processes of <i>D. officinale</i> by binding to the promoters of target genes. This study provides critical insights into the functional roles of Dof transcription factors in Orchidaceae family and establishes a theoretical foundation for molecular breeding and stress resistance improvement in <i>D. officinale</i>.