Identification of Photoperiod- and Phytohormone-Responsive DNA-Binding One Zinc Finger (Dof) Transcription Factors in Akebia trifoliata via Genome-Wide Expression Analysis

As a kind of plant-specific transcription factor (TF), DNA-Binding One Zinc Finger (Dof) is widely involved in the response to environmental change, and as an evolutionarily important perennial plant species, Akebia trifoliata is ideal for studying environmental adaptation. In this study, a total of 41 AktDofs were identified in the A. trifoliata genome. First, the characteristics, including the length, exon number, and chromosomal distribution of the AktDofs and the isoelectric point (PI), amino acid number, molecular weight (MW), and conserved motifs of their putative proteins, were reported. Second, we found that all AktDofs evolutionarily underwent strong purifying selection, and many (33, 80.5%) of them were generated by whole-genome duplication (WGD). Third, we outlined their expression profiles by the use of available transcriptomic data and RT-qPCR analysis. Finally, we identified four candidate genes (AktDof21, AktDof20, AktDof36, and AktDof17) and three other candidate genes (AktDof26, AktDof16, and AktDof12) that respond to long day (LD) and darkness, respectively, and that are closely associated with phytohormone-regulating pathways. Overall, this research is the first to identify and characterize the AktDofs family and is very helpful for further research on A. trifoliata adaptation to environmental factors, especially photoperiod changes.