Transcriptome reveals the effect of oleic acid on the biosynthesis of triterpenoids in Morchella esculenta

Morchella esculenta was a high-value macrofungi that was used in traditional herbal medicine in China. Triterpenoids are the main bioactive compounds in M. esculenta. However, the factors that influence biosynthesis of triterpenoids is little known. In this study, the effect of oleic acid on the biosynthesis of triterpenoids in M. esculenta during liquid fermentation was investigated. The results showed that the levels of triterpenoids in the mycelium increased from 9.80 mg/g to 98.54 mg/g by adding 3% (v/v) of oleic acid. The transcriptomics was used to further analyze the gene expression. The differential genes were mainly involved in carbohydrates metabolism, lipids metabolism, amino acids metabolism, transport and catabolic processes, as well as membrane transport pathways, indicating that the impact of oleic acid on the growth and development of M. esculenta is multifaceted. Additionally, oleic acid increased the production of triterpenoids in M. esculenta by upregulating the expression of triterpenoid synthase genes (AACT, IDI). This study partially analyzed the molecular mechanism of oleic acid inducing the synthesis of triterpenoids in M. esculenta and provided scientific theoretical basis for improving the production of triterpenoids in M. esculenta.