Li Hua, Chen Zhuo, Zhu Wenjun, Ni Xueting, Wang Junru, Fu Lufeng, Chen Jialin, Li Tianpu, Tang Lingxian, Yang Yingjie, Zhang Fukun, Wang Jiashui, Zhou Biyan, Chen Faxing, Lü Peitao
College of Horticulture, Center for Plant Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
National Key Laboratory for Tropical Crop Breeding, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Sanya 572024, China.
Plant Cell. 2024 Dec 23;37(1). doi: 10.1093/plcell/koae282.
The banana (Musa spp.) peel undergoes rapid softening during ripening, leading to finger drop and a shortened shelf life. The regulatory mechanism behind this process remains to be elucidated. In this study, we confirmed the role of peel softening in banana finger drop and uncovered the underlying transcriptional regulatory network. Cell wall-related (CWR) genes were substantially upregulated in both the peel and finger drop zone during ethylene-induced ripening. Transcriptome analysis and genome-wide profiling of chromatin accessibility and transcription factor (TF) binding revealed that two key regulators of fruit ripening, Musa acuminata NAC-like, Activated by apetala3/Pistillata1 (MaNAP1) and MaMADS1, regulate CWR genes by directly binding to their promoters or by targeting other ripening-related TFs to form a hierarchical regulatory network. Notably, MaNAP1 and MaMADS1 were directly targeted by ETHYLENE INSENSITIVE3 (MaEIN3), and MaNAP1 and MaMADS1 associated with tissue-specific histone modifications, enabling them to integrate MaEIN3-mediated ethylene signaling and undergo epigenetic regulation. Overexpression of MaNAP1, MaMADS1, or other identified regulatory TFs upregulated CWR genes and promoted peel softening. Our findings unveil a MaNAP1-MaMADS1-centered regulatory cascade governing banana peel softening and finger drop, offering potential targets for enhancing banana texture and shelf life.
香蕉（Musa spp.）果皮在成熟过程中会迅速软化，导致果指脱落，货架期缩短。这一过程背后的调控机制仍有待阐明。在本研究中，我们证实了果皮软化在香蕉果指脱落中的作用，并揭示了其潜在的转录调控网络。在乙烯诱导的成熟过程中，细胞壁相关（CWR）基因在果皮和果指脱落区域均显著上调。转录组分析以及全基因组染色质可及性和转录因子（TF）结合分析表明，果实成熟的两个关键调节因子，即由apetala3/雌蕊1激活的香蕉NAC样蛋白（MaNAP1）和MaMADS1，通过直接结合CWR基因的启动子或靶向其他与成熟相关的TF来调控CWR基因，从而形成一个分级调控网络。值得注意的是，MaNAP1和MaMADS1直接受乙烯不敏感3（MaEIN3）靶向，并且MaNAP1和MaMADS1与组织特异性组蛋白修饰相关，使其能够整合MaEIN3介导的乙烯信号并接受表观遗传调控。MaNAP1、MaMADS1或其他已鉴定的调控TF的过表达会上调CWR基因并促进果皮软化。我们的研究结果揭示了一个以MaNAP1-MaMADS1为中心的调控级联，它控制着香蕉果皮软化和果指脱落，为改善香蕉质地和延长货架期提供了潜在靶点。
