Overexpression of the isopentenyl diphosphate isomerase gene increases triterpenoids production in Sanghuangporus baumii

Sanghuangporus baumii is a traditional medicinal fungus that contains triterpenoids with important pharmacological effects. However, the level of triterpenoids produced by S. baumii is far below the level demanded for application, and the pathway of triterpenoids biosynthesis is poorly understood. In this study, we established an Agrobacterium tumefaciens -mediated transformation system for the first time and transferred the key gene isopentenyl diphosphate isomerase ( IDI ) involved in triterpenoids biosynthesis into S. baumii . The transcript level of IDI and the total triterpenoids content of the IDI transformant (IT) strain were significantly increased with respect to the wild-type (WT) strain. Then, we investigated the individual triterpenoids contained in S. baumii using metabolome and found 10 individual triterpenoids. All individual triterpenoids produced by IT strain showed the upward trend, were 1.76-10.03 times higher than those produced by the WT strain. Meanwhile, those individual triterpenoids showed significant positive correlation with the IDI gene. The findings provide valuable information about the biosynthetic pathway of triterpenoids and provide a strategy to cultivate S. baumii strains with high triterpenoids content.