背景回顾：Ethylene induces anthocyanin biosynthesis in most fruits, including apple (Malus domestica) and plum (Prunus spp.). By contrast, ethylene inhibits anthocyanin biosynthesis in pear (Pyrus spp.), but the underlying molecular mechanism remains unclear. 

主要发现：In this study, we identified and characterized an ethylene-induced ETHYLENE-RESPONSE FACTOR (ERF) transcription factor, PpERF9, which functions as a transcriptional repressor. 

结果1-ERF9直接抑制MYB114/RAP2.4：Our analyses indicated PpERF9 can directly inhibit expression of the MYB transcription factor gene PpMYB114 by binding to its promoter. Additionally, PpERF9 inhibits the expression of the transcription factor gene PpRELATED TO APETALA2.4 (PpRAP2.4), which activates PpMYB114 expression, by binding to its promoter, thus forming a PpERF9-PpRAP2.4-PpMYB114 regulatory circuit. 

结果2-ERF9-TPL1-MYB114/RAP2.4：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 the PpMYB114 and PpRAP2.4 promoter regions. 

结果3-MYB114/RAP2.4-花色苷：The resulting suppressed expression of these two genes leads to decreased anthocyanin biosynthesis in pear. 

结论：Collectively, these results indicate that ethylene inhibits anthocyanin biosynthesis by a mechanism that involves PpERF9-PpTPL1 complex-mediated histone deacetylation of PpMYB114 and PpRAP2.4.

展望：The data presented herein will be useful for clarifying the relationship between chromatin status and hormone signaling, with implications for plant biology research.

在包括苹果和李子等大多数果实中，乙烯能够诱导花色苷的生物合成。但是，乙烯在梨子果实中反而会抑制花色苷的生物合成，但是潜在的分子机制并不清楚。本文中，作者鉴定到了一个受到乙烯诱导的乙烯响应因子PpERF9，其作为转录抑制因子发挥作用。作者发现，PpERF9能够直接结合到MYB转录因子基因PpMYB114的启动子上抑制其表达。另外，PpERF9还能够抑制转录因子基因PpRAP2.4的表达，而PpRAP2.4能够通过结合PpMYB114基因的启动子激活其表达，从而形成了一个PpERF9-PpRAP2.4-PpMYB114调控环。此外，PpERF9能够通过EAR基序与共抑制因子PpTPL1互作形成复合物，从而移除组蛋白H3上的乙酰基团，将PpMYB114和PpRAP2.4基因启动子区的组蛋白H3乙酰化维持在较低的水平。而PpMYB114和PpRAP2.4基因的表达抑制直接导致了梨子中花色苷生物合成的减少。综上，本文的研究结果揭示了乙烯能够通过PpERF9-PpTPL1复合物介导的PpMYB114和PpRAP2.4组蛋白去乙酰化，抑制花色苷的生物合成。因此，本文的研究建立了一条联系染色质状态与激素信号转导的关联，并为以后植物生物学的相关研究开拓了新的视野。

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