Characterization of Dof family in Pyrus bretschneideri and role of PbDof9.2 in flowering time regulation

DNA binding with One Finger (Dof) proteins are plant-specific transcription factors with highly conserved Dof domain, including C2-C2 type zinc finger motifs. In this study, we identified 45 PbDofs in pear (Pyrusbretschneideri). PbDofs were classified into eight subfamilies by phylogenetic analysis. Conserved motifs of PbDof proteins were analyzed by MEME. PbDofs in subfamily D-1 werehomologous to CDFs in Arabidopsis. In this study, we showed that PbDof9.2 was regulated by both the circadian clock and photoperiod. PbDof9.2-GFP proteinwas localized in the nucleus. Overexpression of PbDof9.2 in Arabidopsis caused delayed flowering time. PbDof9.2 suppressed the flowering time regulator FT and could repress flowering time by promoting activity of PbTFL1a and PbTFL1b promoter. These results suggest that Doftranscription factors have conserved functions in plant development .