Advances in understanding of the biosynthetic pathway and regulatory mechanism of triterpenoid saponins in plants

Triterpenoid saponins are a type of triterpenoid glycoside. Widely distributed in plants, triterpenoid saponins play a role in resisting pathogenic microorganisms and herbivores, but they also have a variety of pharmacological activities that have been widely adopted in medicine, common chemicals, food, and agriculture, to name a few. In recent years, with the development of science and technology and the deepening of research, the basic framework and regulatory mechanisms of triterpenoid saponin biosynthesis in plants have become better understood. Plant triterpenoid saponins have multiple types of complex structures and, although they share a common precursor synthesis pathway, their post-modification stages are highly specific and diverse. In this paper, the biosynthetic pathway, key enzyme genes, transcriptional regulation, and microbial cell engineering of triterpenoid saponins were reviewed, and the future development direction of triterpenoid saponins, which could provide theoretical reference for related research in the abovementioned fields, was prospected.