[Cloning and characterization of a monoterpene synthase gene from Tripterygium wilfordii]

Tripterygium wilfordii is a medicinal plant commonly used in the treatment of rheumatoid arthritis,and with pharmacological activities in anti-tumor and obesity treatment. The known active ingredients in T. wilfordii are mainly terpenoids,but with very low content. Therefore,the analysis of the biosynthesis pathway of terpenoids in T. wilfordii has become a research hotspot to solve the problem of its resources. Terpenoid synthase( TPS) is a key enzyme that catalyzes the formation of a wide variety of terpenoid skeletons. In this study,a gene fragment with an ORF of 1 785 bp was cloned from T. wilfordii. Bioinformatics analysis was performed using NCBI's BLASTP,ProtParam and Interpro online tools and MEGA 6.0 software. The response of this gene to methyl jasmonate was also detected by real-time fluorescent quantitative PCR,and its catalytic function was verified by prokaryotic expression and in vitro enzymatic assay. Bioinformatics analysis indicated that the amino acid sequence encoded by this gene had both N-terminal domain and C-terminal domain of TPS,as well as the DDxx D conserved domain of the class I of TPS family. And Tw MTS gathered together with TPS-b subfamily in the Neighbor-Joining Tree constructed with known homologous TPSs. The results of RT-PCR showed that 50 μmol·L-1 MeJA 12 h could increase the expression of Tw MTS to 735 times in the control group at 12 h,and 1 644 times at 24 h. In addition,in vitro enzymatic reaction results showed that Tw MTS can catalyze the production of β-citronellol with GPP as substrate,indicating that Tw MTS was a monoterpene synthase. The above results provided a new element for the synthetic biology database of T. wilfordii terpenoids,and laid the foundation for future biosynthesis research.