Members of the TEOSINTE BRANCHED 1/CYCLOIDEA/PROLIFERATING CELL FACTOR (TCP) family are plant-specific transcription factors regulating numerous growth and development processes, including the floral transition. However, the roles of TCP genes in regulating the flowering of pear remain unknown. Here, we identified PbTCP2 as a transcription factor associated with flowering. PbTCP2 was identified as a typical nucleus-located transcription factor without self-activation activity. We verified the biological function of PbTCP2 in accelerating floral transition via heterologous overexpression in Arabidopsis thaliana. Compared with wild-type Arabidopsis lines, PbTCP2-overexpressing plants displayed elevated transcript levels of flowering activators, whereas transcript levels of flowering repressors, including PbSVP (SHORT VEGETATIVE PHASE), were significantly decreased. Yeast one-hybrid and electrophoretic mobility shift assays indicated that PbTCP2 protein directly binds to the promoter of PbSVP. The transcriptional repression activity of PbTCP2 on PbSVP was further confirmed by dual-luciferase assays. We further showed that PbTCP4 interacts with PbTCP2, as evidenced by yeast two-hybrid, bimolecular fluorescence complementation, and pull-down assays. Notably, forming a complex with PbTCP2, PbTCP4 synergistically enhanced this repression, a conclusion supported by dual-luciferase and GUS staining assays. Overexpression of PbTCP4 also promoted flowering in Arabidopsis. Collectively, these findings confirm a PbSVPcontrolled flowering mechanism regulated by the PbTCP4-PbTCP2 complex in pear, shedding light on the molecular mechanisms underlying flowering regulation in perennial crops.
