National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan 430070, China; National Research Center for Apple Engineering and Technology, Shandong Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, Shandong 271018, China.
National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan 430070, China.
Plant Commun. 2024 Nov 11;5(11):101065. doi: 10.1016/j.xplc.2024.101065. Epub 2024 Aug 20.
Carotenoid biosynthesis is closely associated with abscisic acid (ABA) during the ripening process of non-climacteric fruits, but the regulatory mechanism that links ABA signaling to carotenoid metabolism remains largely unclear. Here, we identified two master regulators of ABA-mediated citrus fruit coloration, CsERF110 and CsERF53, which activate the expression of carotenoid metabolism genes (CsGGPPS, CsPSY, CsPDS, CsCRTISO, CsLCYB2, CsLCYE, CsHYD, CsZEP, and CsNCED2) to facilitate carotenoid accumulation. Further investigations showed that CsERF110 not only activates the expression of CsERF53 by binding to its promoter but also interacts with CsERF53 to form the transcriptional regulatory module CsERF110-CsERF53. We also discovered a positive feedback regulatory loop between the ABA signal and carotenoid metabolism regulated by the transcriptional regulatory module CsERF110-CsERF53. Our results reveal that the CsERF110-CsERF53 module responds to ABA signaling, thereby orchestrating citrus fruit coloration. Considering the importance of carotenoid content for citrus and many other carotenoid-rich crops, the revelation of molecular mechanisms that underlie ABA-mediated carotenoid biosynthesis in plants will facilitate the development of transgenic/gene-editing approaches, further contributing to improving the quality of citrus and other carotenoid-rich crops.
类胡萝卜素生物合成与非跃变型果实成熟过程中的脱落酸（ABA）密切相关，但 ABA 信号与类胡萝卜素代谢之间的调控机制在很大程度上仍不清楚。在这里，我们鉴定了两个 ABA 介导的柑橘果实着色的主调控因子 CsERF110 和 CsERF53，它们激活了类胡萝卜素代谢基因（CsGGPPS、CsPSY、CsPDS、CsCRTISO、CsLCYB2、CsLCYE、CsHYD、CsZEP 和 CsNCED2）的表达，促进了类胡萝卜素的积累。进一步的研究表明，CsERF110 不仅通过结合其启动子激活 CsERF53 的表达，还与 CsERF53 相互作用形成转录调控模块 CsERF110-CsERF53。我们还发现了 ABA 信号和类胡萝卜素代谢之间的正反馈调节环，该调节环受转录调控模块 CsERF110-CsERF53 调控。我们的研究结果表明，CsERF110-CsERF53 模块响应 ABA 信号，从而协调柑橘果实着色。考虑到类胡萝卜素含量对柑橘和许多其他富含类胡萝卜素的作物的重要性，揭示植物中 ABA 介导的类胡萝卜素生物合成的分子机制将有助于开发转基因/基因编辑方法，进一步有助于提高柑橘和其他富含类胡萝卜素的作物的品质。
