Song Zunyang, Chen Hangcong, Lai Xiuhua, Wang Lihua, Yao Yulin, Qin Jiajia, Pang Xuequn, Zhu Hong, Chen Weixin, Li Xueping, Zhu Xiaoyang
Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables/Engineering Research Center for Postharvest Technology of Horticultural Crops in South China, Ministry of Education, College of Horticulture, South China Agricultural University, Guangzhou, Guangdong 510642, China.
Key Laboratory of Food Processing Technology and Quality Control in Shandong Province, College of Food Science and Engineering, Shandong Agricultural University, Tai'an 271018, China.
Plant Cell Physiol. 2024 Jan 19;65(1):49-67. doi: 10.1093/pcp/pcad115.
As zinc finger protein transcription factors (TFs), the molecular mechanism of Cys-Cys-Cys-His (CCCH) TFs in regulating plant development, growth and stress response has been well studied. However, the roles of CCCH TFs in fruit ripening are still obscure. Herein, we report that MaCCCH33-like2 TF and its associated proteins modulate the fruit softening of 'Fenjiao' bananas. MaCCCH33-like2 interacts directly with the promoters of three genes: isoamylase2 (MaISA2), sugar transporter14-like (MaSUR14-like) and β-d-xylosidase23 (MaXYL23), all of which are responsible for encoding proteins involved in the degradation of starch and cell wall components. Additionally, MaCCCH33-like2 forms interactions with abscisic acid-insensitive 5 (ABI5)-like and ethylene F-box protein 1 (MaEBF1), resulting in enhanced binding and activation of promoters of genes related to starch and cell wall degradation. When MaCCCH33-like2 is transiently and ectopically overexpressed in 'Fenjiao' banana and tomato fruit, it facilitates softening and ripening processes by promoting the degradation of cell wall components and starch and the production of ethylene. Conversely, the temporary silencing of MaCCCH33-like2 using virus-induced gene silencing (VIGS) inhibits softening and ripening in the 'Fenjiao' banana by suppressing ethylene synthesis, as well as starch and cell wall degradation. Furthermore, the promoter activity of MaCCCH33-like2 is regulated by MaABI5-like. Taken together, we have uncovered a novel MaCCCH33-like2/MaEBF1/MaABI5-like module that participates in fruit softening regulation in bananas.
作为锌指蛋白转录因子（TFs），半胱氨酸-半胱氨酸-半胱氨酸-组氨酸（CCCH）TFs在调节植物发育、生长和应激反应方面的分子机制已得到充分研究。然而，CCCH TFs在果实成熟中的作用仍不清楚。在此，我们报道MaCCCH33-like2 TF及其相关蛋白调节‘粉蕉’果实的软化。MaCCCH33-like2直接与三个基因的启动子相互作用：异淀粉酶2（MaISA2）、类糖转运蛋白14（MaSUR14-like）和β-d-木糖苷酶23（MaXYL23），这三个基因均负责编码参与淀粉和细胞壁成分降解的蛋白质。此外，MaCCCH33-like2与脱落酸不敏感5（ABI5）样蛋白和乙烯F-box蛋白1（MaEBF1）形成相互作用，导致与淀粉和细胞壁降解相关基因的启动子结合和激活增强。当MaCCCH33-like2在‘粉蕉’香蕉和番茄果实中瞬时异位过表达时，它通过促进细胞壁成分和淀粉的降解以及乙烯的产生来促进软化和成熟过程。相反，使用病毒诱导基因沉默（VIGS）暂时沉默MaCCCH33-like2可通过抑制乙烯合成以及淀粉和细胞壁降解来抑制‘粉蕉’香蕉的软化和成熟。此外，MaCCCH33-like2的启动子活性受MaABI5-like调控。综上所述，我们发现了一个参与香蕉果实软化调控的新型MaCCCH33-like2/MaEBF1/MaABI5-like模块。
