A multifunctional oxidosqualene cyclase from that produces both α- and β-amyrin.

is a rich source of triterpenoids, containing many types of triterpenes with high chemical diversity and interesting pharmacological properties. The cDNA of the multifunctional oxidosqualene cyclase (, GenBank accession number: MH161182), consisting of a 2289 bp open reading frame and coding for 762 amino acids, was cloned from the stems and roots of . Phylogenetic analysis using OSC genes from other plants suggested that might be a mixed-amyrin synthase. The coding sequence was cloned into the expression vector pYES2 and transformed into the yeast . The resulting products were analysed by GC-MS. Surprisingly, although it showed 76% sequence identity to lupeol synthase from , was found to be a multifunctional triterpene synthase producing both α- and β-amyrin, the precursors of ursane and oleanane type triterpenes, respectively. qRT-PCR analysis revealed that the transcript of accumulated mainly in roots and stems. Taken together, our findings contribute to the knowledge of key genes in the pentacyclic triterpene biosynthesis pathway.