Salicylic acid promotes terpenoid synthesis in the fungi Sanghuangporus baumii

Sanghuangporus baumii is a medicinal fungi with anti‐inflammatory, liver protection and antitumour effects. Terpenoids are one of the main medicinal ingredients of S. baumii. However, terpenoid production by wild‐type S. baumii cannot meet the market demand, which affects its application in medical care. Therefore, exploring how to increase terpenoid content in S. baumii is a promising path in this research field. Salicylic acid (SA) is a secondary metabolite. In this study, a concentration of 350 μmol/L SA was added into fungal cultivations for 2 and 4 days, and then the transcriptome and metabolome of untreated mycelia and treated with SA were analysed. The expression of some genes in the terpenoids biosynthesis pathway increased in SA‐induced cultivations, and the content of isopentenyl pyrophosphate (IPP) and geranylgeranyl‐PP (GGPP) increased significantly as well as the contents of triterpenoids, diterpenoids, sesquiterpenoids and carotenoids. The gene FPS was considered to be a key gene regulating terpenoid biosynthesis. Therefore, FPS was overexpressed in S. baumii by Agrobacterium tumefaciens‐mediated genetic transformation. The gene FPS and its downstream gene (LS) expression levels were confirmed to be increased in the FPS overexpressing transformant, and terpenoid content was 36.98% higher than that of the wild‐type strain in the evaluated cultivation conditions.