Some triterpenoid saponins, which are used to treat various medical conditions, are decorated with rare sugars. However, due to the lack of characterized biosynthetic pathways and limited knowledge of the enzymes responsible for producing these sugars, it has been challenging to produce these compounds in a sustainable manner. To address this, our laboratory is working to improve our understanding of the enzymes and pathways involved in the biosynthesis of these special sugars, and to develop strategies for producing valuable triterpenoids with rare sugars by studying triterpenoid-related glycosyltransferases.