TCP transcription factor PpTCP20 is involved in peach bud endodormancy by inhibiting PpDAM5/PpDAM6 and interacting with PpABF2.

The dormancy-associated MADS-box genes PpDAM5 and PpDAM6 have been shown to play an important role in bud endodormancy. However, the molecular regulatory mechanism of PpDAM5 and PpDAM6 involvement in peach endodormancy is still unclear. Here, through yeast one-hybrid (Y1H) screening, we isolated PpTCP20, a TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR (TCP) transcription factor in the peach cultivar 'Zhongyou 4' (Prunus persica var. nectarina). PpTCP20 was localized in the nucleus and was capable of forming a homodimer. The electrophoretic mobility shift assay (EMSA) demonstrated that PpTCP20 binds to a GCCCR element in the promoter of PpDAM5 and PpDAM6, and transient dual luciferase (Dual-LUC) experiments showed that PpTCP20 inhibited PpDAM5 and PpDAM6 expression as the peach flower bud endodormancy release period approached. Furthermore, PpTCP20 interacted with PpABF2 to form heterodimers to regulate peach bud endodormancy, and the content of abscisic acid (ABA) decreased with the release of peach flower bud endodormancy. In addition, PpTCP20 inhibited PpABF2 expression to regulate peach flower bud endodormancy. Taken together, our results suggest that PpTCP20 regulates peach flower bud endodormancy by negatively regulating the expression of PpDAM5, PpDAM6 and interacting with PpABF2. Therefore, these results reveal the novel mechanism regulating bud endodormancy in perennial deciduous trees, including peach.