NO Activates the Triterpenoid Biosynthetic Pathway in Through Multilevel Signaling Regulation to Enhance Its Production.

Triterpenoids are the bioactive components in with extensive medicinal prospects, but their low content in fermentation production is the main limiting factor for their application. This study focuses on nitric oxide (NO), an important signaling molecule within organisms, aiming to explore its inducing effect on the synthesis of triterpenes in and the potential signaling transduction mechanisms involved. Compared with the control group, the content of representative triterpenoid betulin increased by 70.59% after adding the NO donor sodium nitroprusside. Gene expression level detection revealed that NO mainly promotes its biosynthesis by activating the transcription of key enzyme genes in the downstream pathway of betulin biosynthesis, thereby increasing its abundance. Tracing upstream, the NO signal was found to induce the upregulation of genes related to cellular antioxidant and calcium ion signaling pathways. Notably, responded strongly to the NO signal, participating in the regulation of cytoplasmic Ca concentration by altering the Ca concentration of mitochondria together with and Additionally, the signaling of changes in Ca concentrations is likely to crosstalk with the reactive oxygen species (ROS) signaling pathway. The increase in enzyme activity of after NO induction confirmed the activation of the ROS signaling pathway. It works in synergy with and to reduce oxidative damage and promote downstream triterpenoid biosynthesis. This study not only contributes to clarify the signaling pathways regulating NO-mediated triterpenoid biosynthesis but also provides a theoretical basis for the efficient production of triterpenoid active components in .