Genome-wide identification of the Dofs family and analysis of the expression pattern under different hormone treatments in blueberry

DNA-binding zinc finger ( Dof ) proteins are plant-specific transcription factors involved in growth, stress responses, and hormone signaling. Although genome-wide analyses of Dof genes have been reported in various plant species, the hormone-responsive expression patterns of Dof genes in blueberries have not yet been explored. In this study, we conducted the first genome-wide identification of the Dof gene family in blueberries, identifying 32 Dof genes from the Vaccinium darrowii genome. Notably, a comparative analysis of expression responses to five hormonal treatments (IAA, GA, SA, ABA, and MeJA) revealed significant differences in their temporal induction patterns: IAA and SA triggered strong upregulation of responsive Dof genes in the early phase, whereas GA-induced upregulation occurred primarily in the late phase. This hormone-specific temporal pattern has not been highlighted in previous studies of the Dof family in other species. Promoter analysis further supported these findings, revealing an enrichment of IAA- and SA-responsive cis-regulatory elements. Based on comprehensive expression profiling, we identified six Dof candidate genes potentially involved in the upregulation of IAA and GA biosynthesis, as well as five Dof candidate genes associated with ABA, SA, and MeJA biosynthesis. These candidate genes provide specific targets for future functional studies. Overall, this study not only provides a comprehensive catalog of blueberry Dof genes but also uncovers distinct hormone-specific temporal expression patterns, offering a foundation for understanding their potential roles in hormone signaling.