Xu Yan, Du Jinge, Hao Ruili, Ma Siqi, Ma Yujiao, Zhou Gongke, Hu Ruibo, Li Shengjun
CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Shandong Energy Institute, Qingdao New Energy Shandong Laboratory, Qingdao, PR China.
University of Chinese Academy of Sciences, Beijing, PR China.
Nat Commun. 2025 Apr 30;16(1):4065. doi: 10.1038/s41467-025-59268-2.
Pectin is an abundant polysaccharide with essential roles in various biological processes. Despite considerable advances in understanding the regulatory mechanisms of pectin biosynthesis, the influence of phytohormones on this process remains unclear. Here we report that gibberellins (GA) promotes pectin biosynthesis in Arabidopsis. The DELLA proteins, as GA signaling repressors, interact with TRANSPARENT TESTA GLABRA2 (TTG2) and components of the MYB-bHLH-WD40 (MBW) complex, the key regulators of pectin biosynthesis, to repress their transcriptional regulatory activities. Furthermore, the MBW proteins and TTG2 physically interact and synergistically activate the downstream target GLABRA2, whereas this interaction and collaboration are competitively attenuated by DELLAs. Genetic analyses validate that GA-mediated pectin biosynthesis relies on functional TTG2 and MBW proteins. Moreover, the pectin biosynthesis mediated by the GA-DELLA-MBW-TTG2 module contributes to GA-regulated seedling growth. Our findings reveal the significance of the GA-DELLA-MBW-TTG2 signaling cascade in the regulation of pectin biosynthesis and plant development.
果胶是一种丰富的多糖，在各种生物过程中发挥着重要作用。尽管在理解果胶生物合成的调控机制方面取得了相当大的进展，但植物激素对这一过程的影响仍不清楚。在此，我们报道赤霉素（GA）促进拟南芥中的果胶生物合成。DELLA蛋白作为GA信号抑制因子，与透明种皮光滑2（TTG2）以及果胶生物合成的关键调节因子MYB-bHLH-WD40（MBW）复合体的组分相互作用，以抑制它们的转录调节活性。此外，MBW蛋白和TTG2发生物理相互作用并协同激活下游靶标光滑2，而这种相互作用和协作被DELLA蛋白竞争性减弱。遗传分析证实GA介导的果胶生物合成依赖于功能性的TTG2和MBW蛋白。此外，由GA-DELLA-MBW-TTG2模块介导的果胶生物合成有助于GA调节的幼苗生长。我们的研究结果揭示了GA-DELLA-MBW-TTG2信号级联在果胶生物合成和植物发育调控中的重要性。
