Involvement of sweet cherry PavPP2C59 in negatively regulating fruitlet abscission and fruit ripening

Abnormal fruitlet drop poses a significant challenge to the cherry industry, and ABA is known to be involved in organ abscission. The protein phosphatase 2Cs (PP2Cs) plays a crucial role in ABA signaling; however, their functions in the abscission of sweet cherry fruitlets remain unexplored. Currently, 17 F-clade PP2C members were identified in the sweet cherry, among which PavPP2C59 was significantly downregulated in fruit ripening and abscission. The PavPP2C59 promoter exhibited GUS expression activity in the abscission petals of Arabidopsis thaliana, which decreased during silique development and ripening and responded to IAA or ABA treatment. Overexpression of PavPP2C59 in A. thaliana promoted root elongation, delayed petal abscission, and shortened silique length. Yeast one-hybrid and dual-luciferase reporter assays demonstrated that PavDOF18 and PavERF110 interacted with the PavPP2C59 promoter and inhibited its transcription, respectively. PavDOF18 and PavERF110 are localized in the nucleus as transcriptional repressors and have regulatory functions in fruit development and abscission. Y2H and luciferase complementation imaging assays revealed that PavPP2C59 interacts with PavRDUF1, which may lead to its ubiquitination and subsequent degradation. These findings indicate that PavPP2C59 negatively regulates fruitlet abscission and ripening in sweet cherry, providing new insights for a better understanding of fruit abscission in plants.