AbstractEthylene induces anthocyanin biosynthesis in most fruits, including apple (Malus domestica) and plum (Prunusspp.). By contrast, ethylene inhibits anthocyanin biosynthesis in pear (Pyrusspp.), but the underlying molecular mechanism remains unclear. In this study, we identified and characterized an ethylene-induced ETHYLENE RESPONSE FACTOR (ERF) transcription factor, PpETHYLENE RESPONSE FACTOR9 (PpERF9), which functions as a transcriptional repressor. Our analyses indicated PpERF9 can directly inhibit expression of the MYB transcription factor genePpMYB114by binding to its promoter. Additionally, PpERF9 inhibits the expression of the transcription factor genePpRELATED TO APETALA2.4(PpRAP2.4), which activatesPpMYB114expression, by binding to its promoter, thus forming a PpERF9-PpRAP2.4-PpMYB114 regulatory circuit. Furthermore, PpERF9 interacts with the co-repressor PpTOPLESS1 (PpTPL1) via EAR motifs to form a complex that removes the acetyl group on histone H3 and maintains low levels of acetylated H3 in thePpMYB114andPpRAP2.4promoter regions. The resulting suppressed expression of these 2 genes leads to decreased anthocyanin biosynthesis in pear. Collectively, these results indicate that ethylene inhibits anthocyanin biosynthesis by a mechanism that involves PpERF9-PpTPL1 complex-mediated histone deacetylation ofPpMYB114andPpRAP2.4. The data presented herein will be useful for clarifying the relationship between chromatin status and hormone signaling, with implications for plant biology research.