Cloning, molecular properties and differential expression analysis of the isopentenyl diphosphate isomerase gene in Sanghuangporus baumii

Sanghuangporus baumii (Pilát) L.W. Zhou & Y.C. Dai, a popular medicinal fungus, has been used to treat several diseases by its triterpenoids bioactive ingredient for many years. However, the triterpenoids content of S. baumii is low and their biosynthesis mechanisms are not clearly understood. In order to reveal the regulation mechanism of triterpenoids biosynthesis in S. baumii, the cDNA encoding isopentenyl diphosphate isomerase (IDI) involved in triterpenoids biosynthesis was cloned and named as SbIDI (GenBank number MK955885). The open reading frame of the SbIDI gene cDNA comprised 792 bp and encoded a polypeptide of 263 amino acids with a predicted protein molecular weight of 29.80 kDa. The transcript level of the SbIDI gene and triterpenoids content of S. baumii were detected at different developmental stages. The results showed that the transcript level of the SbIDI gene and triterpenoids content had almost the same trend of change, increased first and then decreased dynamically. The highest transcript level of the SbIDI gene occurred earlier than the highest triterpenoids content, indicating that the SbIDI gene may play an important role in triterpenoids biosynthesis in S. baumii. Moreover, the SbIDI gene cDNA was successfully expressed in Escherichia coli BL21 (DE3), and the protein bands were consistent with the prediction.The results will lay a foundation for further study of the function of the SbIDI gene.