Li Tong, Liu Li, Yang Guangxin, Cai Yingcong, Wang Yingda, Sun Bowen, Sun Le, Liu Weiting, Wang Aide
Key Laboratory of Fruit Postharvest Biology (Liaoning Province), Key Laboratory of Protected Horticulture (Ministry of Education), National & Local Joint Engineering Research Center of Northern Horticultural Facilities Design & Application Technology (Liaoning), College of Horticulture, Shenyang Agricultural University, Shenyang, 110866, China.
Liaoning Institute of Pomology, Xiongyue, 115009, China.
Adv Sci (Weinh). 2025 Jun;12(22):e2417393. doi: 10.1002/advs.202417393. Epub 2025 Apr 9.
Fruit of most apple varieties soften after harvest, and although the hormone ethylene is known to induce softening, the associated pathway is not well resolved. In this study, it is determined that MdEAEL1 (Ethylene-activated E3 ubiquitin Like 1) is specifically expressed during apple fruit postharvest storage, activated by ethylene, and interacts with the transcription factor MdZFP3 (zinc finger protein3). MdZFP3 is found to rely on an EAR (ethylene-responsive element binding factor-associated amphiphilic repression) motif to form a transcriptional repression complex with MdTPL4 (TOPLESS4)-MdHDA19 (histone deacetylase19), thereby downregulating the histone acetylation levels of the promoters of a range of cell wall degradation-related genes and inhibiting their transcription. MdEAEL1 ubiquitinates and degrades MdZFP3, leading to the disassembly of the MdZFP3-MdTPL4-MdHDA19 transcriptional repression complex. This process promotes the transcription of cell wall degradation-related genes, resulting in fruit softening during storage. Furthermore, the disassembly of the MdZFP3-MdTPL4-MdHDA19 transcriptional repression complex, mediated by MdEAEL1, upregulates the transcription of MdEAEL1 itself, creating a feedback loop that further promotes softening. This study elucidates the interplay between post-translational modifications of a transcription factor and its epigenetic modification to regulate fruit softening, and highlights the complexity of ethylene-induced softening.
大多数苹果品种的果实采后会软化，尽管已知激素乙烯可诱导果实软化，但其相关途径尚未完全明确。在本研究中，确定了MdEAEL1（乙烯激活的E3泛素样蛋白1）在苹果果实采后贮藏期间特异性表达，受乙烯激活，并与转录因子MdZFP3（锌指蛋白3）相互作用。研究发现，MdZFP3依赖EAR（乙烯反应元件结合因子相关两亲性抑制）基序与MdTPL4（TOPLESS4）-MdHDA19（组蛋白去乙酰化酶19）形成转录抑制复合物，从而下调一系列细胞壁降解相关基因启动子的组蛋白乙酰化水平并抑制其转录。MdEAEL1使MdZFP3泛素化并降解，导致MdZFP3-MdTPL4-MdHDA19转录抑制复合物解体。这一过程促进了细胞壁降解相关基因的转录，导致贮藏期间果实软化。此外，由MdEAEL1介导的MdZFP3-MdTPL4-MdHDA19转录抑制复合物的解体上调了MdEAEL1自身的转录，形成一个反馈环，进一步促进果实软化。本研究阐明了转录因子的翻译后修饰与其表观遗传修饰之间的相互作用对果实软化的调控作用，并突出了乙烯诱导果实软化的复杂性。
