Wang Wei, Chen Yang, Jiang Yabo, Tang Guangcai, Guo Luyue, Qiao Gaozheng, Liu Shihao, Tan Bin, Cheng Jun, Zhang Langlang, Ye Xia, Wang Xiaobei, Zhang Haipeng, Zheng Xianbo, Zhang Shiwen, Feng Jiancan
College of Horticulture, Henan Agricultural University, 218 Pingan Road, 450046, Zhengzhou, China; Henan Engineering and Technology Center for Peach Germplasm Innovation and Utilization, Zhengzhou, 450046, China; International Joint Laboratory of Henan Horticultural Crop Biology, Henan Agricultural University, Zhengzhou, 450046, China.
College of Horticulture, Henan Agricultural University, 218 Pingan Road, 450046, Zhengzhou, China; Henan Engineering and Technology Center for Peach Germplasm Innovation and Utilization, Zhengzhou, 450046, China.
Plant Physiol Biochem. 2025 Mar;220:109537. doi: 10.1016/j.plaphy.2025.109537. Epub 2025 Jan 21.
The basic helix-loop-helix (bHLH) transcription factors (TFs) play important roles in various plant developmental and biological processes. However, the precise mechanisms by which bHLH TFs regulate fruit ripening warrant further investigation. Polyamine oxidase (PAO) is crucial for polyamine (PA) catabolism and plays crucial roles in fruit ripening. However, the regulatory mechanism of PAO gene expression during fruit ripening remains largely unexplored. In this study, we identified a peach bHLH TF, PpeUNE12, which directly binds to and activates the promoter of PpePAO1. Silencing PpeUNE12 substantially increased PA accumulation and delayed peach fruit ripening, while overexpressing PpeUNE12 decreased PA accumulation and accelerated peach fruit ripening. Additionally, anthocyanin content decreased in PpeUNE12-silenced fruits but increased in PpeUNE12-overexpressing peach fruits compared to the control. RNA-seq and RT-qPCR analyses revealed that the majority of genes involved in anthocyanin biosynthesis, including PpeF3H, PpeCHS, PpeDFR, PpeUFGT and PpeMYB10.1 exhibited down-regulation in fruits with silenced PpeUNE12, while these genes were up-regulated in fruits overexpressing PpeUNE12. Although PpeUNE12 exhibited no direct binding to the promoters of PpeUFGT and PpeMYB10.1, it substantially activated their activity. This investigation is the first to provide evidence that bHLH regulates fruit maturation via promoting both PA catabolism and anthocyanin synthesis. It reveals a novel mechanism of bHLH in regulating fruit ripening and enhances our comprehension of the regulatory mechanism of PA catabolism and anthocyanin synthesis during fruit maturation.
基本螺旋-环-螺旋（bHLH）转录因子在植物的各种发育和生物学过程中发挥着重要作用。然而，bHLH转录因子调控果实成熟的精确机制仍有待进一步研究。多胺氧化酶（PAO）对多胺（PA）分解代谢至关重要，在果实成熟过程中发挥关键作用。然而，果实成熟过程中PAO基因表达的调控机制在很大程度上仍未被探索。在本研究中，我们鉴定出一个桃bHLH转录因子PpeUNE12，它直接结合并激活PpePAO1的启动子。沉默PpeUNE12显著增加了PA积累并延缓了桃果实成熟，而过表达PpeUNE12则降低了PA积累并加速了桃果实成熟。此外，与对照相比，PpeUNE12沉默果实中的花青素含量降低，而PpeUNE12过表达的桃果实中的花青素含量增加。RNA测序和逆转录定量PCR分析表明，参与花青素生物合成的大多数基因，包括PpeF3H、PpeCHS、PpeDFR、PpeUFGT和PpeMYB10.1，在PpeUNE12沉默的果实中表现出下调，而这些基因在过表达PpeUNE12的果实中上调。尽管PpeUNE12未表现出与PpeUFGT和PpeMYB10.1启动子的直接结合，但它显著激活了它们的活性。本研究首次提供证据表明bHLH通过促进PA分解代谢和花青素合成来调控果实成熟。它揭示了bHLH调控果实成熟的新机制，并增强了我们对果实成熟过程中PA分解代谢和花青素合成调控机制的理解。
