Identification of DNA-binding with one finger (DOF) transcription factor family and functional study of CsDOF10 in sweet orange (Citrus sinensis)

DOF transcription factors (TFs), which are specific to plants and contain zinc finger motifs, play a crucial role in various physiological and biochemical processes throughout plant life. Citrus sweet orange, one of the most economically and aesthetically valuable fruit crops globally, has not been the subject of thorough systematic analyses regarding its CsDOF gene members and their functions. In this study, we identified 24 CsDOF genes that are distributed unevenly across 19 scaffolds in sweet orange. We provide a detailed overview of these CsDOF genes, including their scaffold locations, phylogenetic relationships with the Arabidopsis DOF family, and structural characteristics. The phylogenetic analysis grouped the 60 DOF members identified from citrus and Arabidopsis into six main groups. Additionally, we detected distinct expression patterns of CsDOF genes under both normal and drought conditions using qRT-qPCR. Notably, the CsDOF10 gene showed high expression level in response to drought treatment, suggesting a potential adaptation to drought stress. The overexpression of CsDOF10 in Arabidopsis increases the plant's resistance to drought, stimulates the growth of primary roots, and suppresses the formation of lateral roots. CsDOF10 is located in the nucleus and has transcriptional activation activity. Moreover, additional studies have demonstrated that the expression of CsDOF10 is influenced by the upstream regulatory factor CsKNOX9. Our discoveries offer significant insights for future investigations into the ability of citrus sweet orange to cope with drought stress.