Genome-Based Identification of the Dof Gene Family in Three Species and Their Responses to Heat Stress in .

As an important genus in Orchidaceae, has rich ecological diversity and significant economic value. DNA binding with one zinc finger (Dof) proteins are pivotal plant-specific transcription factors that play crucial roles in the growth, development, and stress response of plants. Although the Dof genes have been identified and functionally analyzed in numerous plants, exploration in Orchidaceae remains limited. We conducted a thorough analysis of the Dof gene family in , , and . In total, 91 Dof genes (27 s, 34 s, 30 s) were identified, and Dof genes were divided into five groups (I-V) based on phylogenetic analysis. All Dof proteins have motif 1 and motif 2 conserved domains and over half of the genes contained introns. Chromosomal localization and collinearity analysis of Dof genes revealed their evolutionary relationships and potential gene duplication events. Analysis of -elements in s, s, and s promoters showed that light-responsive -elements were the most common, followed by hormone-responsive elements, plant growth-related elements, and abiotic stress response elements. Dof proteins in three species primarily exhibit a random coil structure, while homology modeling exhibited significant similarity. In addition, RT-qPCR analysis showed that the expression levels of nine changed greatly under heat stress. , , , , and showed varying degrees of upregulation. Most upregulated genes under heat stress belong to group I, indicating that the Dof genes in group I have great potential for high-temperature resistance. In conclusion, our study systematically demonstrated the molecular characteristics of Dof genes in different species, preliminarily revealed the patterns of heat stress, and provided a reference for further exploration of stress breeding in orchids.