A Review on Saponin Biosynthesis and its Transcriptomic Resources in Medicinal Plants

Saponins are naturally occurring glycosides which are produced by various plant species with diverse biological properties. The surface-active properties of saponins differentiates them from other glycosides. They are classified mainly into steroid and triterpenoid glycosides based on the structure of hydrophobic aglycone unit. The synthesis of saponins and the genes involved in its biosynthesis can be identified by transcriptome profiling. Using high-throughput sequencing technologies, the steroid or triterpenoid saponin biosynthesis related genes have been discovered which can help boosting the molecular research in this biosynthetic pathway. This review mainly illustrates the importance of saponins and the transcriptome resources of important medicinal plants for identifying genes related to its biosynthesis. Furthermore, the significance of unexplored plants which are rich sources of saponins in future studies are also discussed in the current review.