Publications

• Functional characterization of triterpene synthases in <i>Cibotium barometz</i>.

  Ji Z., Fan B., Chen Y., Yue J., Chen J., Zhang R., Tong Y., Liu Z., Liang J., Duan L.

  <i>Cibotium barometz</i> (Linn.) J. Sm., a tree fern in the Dicksoniaceae family, is an economically important industrial exported plant in China and widely used in Traditional Chinese Medicine. <i>C. barometz</i> produces a range of bioactive triterpenes and their metabolites. However, the biosyn ... >> More

  <i>Cibotium barometz</i> (Linn.) J. Sm., a tree fern in the Dicksoniaceae family, is an economically important industrial exported plant in China and widely used in Traditional Chinese Medicine. <i>C. barometz</i> produces a range of bioactive triterpenes and their metabolites. However, the biosynthetic pathway of triterpenes in <i>C. barometz</i> remains unknown. To clarify the origin of diverse triterpenes in <i>C. barometz</i>, we conducted <i>de novo</i> transcriptome sequencing and analysis of <i>C. barometz</i> rhizomes and leaves to identify the candidate genes involved in <i>C. barometz</i> triterpene biosynthesis. Three <i>C. barometz</i> triterpene synthases (CbTSs) candidate genes were obtained. All of them were highly expressed in <i>C. barometz</i> rhizomes, consisting of the accumulation pattern of triterpenes in <i>C. barometz</i>. To characterize the function of these CbTSs, we constructed a squalene- and oxidosqualene-overproducing yeast chassis by overexpressing all the enzymes in the MVA pathway under the control of GAL-regulated promoter and disrupted the GAL80 gene in <i>Saccharomyces cerevisiae</i> simultaneously. Heterologous expressing CbTS1, CbTS2, and CbTS3 in engineering yeast strain produced cycloartenol, dammaradiene, and diploptene, respectively. Phylogenetic analysis revealed that CbTS1 belongs to oxidosqualene cyclase, while CbTS2 and CbTS3 belong to squalene cyclase. These results decipher enzymatic mechanisms underlying the origin of diverse triterpene in <i>C. barometz</i>. << Less

  Synth Syst Biotechnol 8:437-444(2023) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• Dammaradiene synthase, a squalene cyclase, from Dryopteris crassirhizoma Nakai.

  Shinozaki J., Shibuya M., Masuda K., Ebizuka Y.

  Ferns produce a variety of cyclic triterpene hydrocarbons in large amount. Squalene cyclases (SCs) are responsible enzymes for formation of cyclic triterpene hydrocarbon skeletons. Although more than ten bacterial SCs have been cloned and four of them characterized for their enzymatic products, th ... >> More

  Ferns produce a variety of cyclic triterpene hydrocarbons in large amount. Squalene cyclases (SCs) are responsible enzymes for formation of cyclic triterpene hydrocarbon skeletons. Although more than ten bacterial SCs have been cloned and four of them characterized for their enzymatic products, the only example of a fern SC is ACH, from Adiantum capillus-veneris, which produces hydroxyhopane. To obtain a deeper understanding of the molecular evolution of SCs and the origin of the structural diversity of fern triterpenes, further cloning and characterization of SCs have been pursued. In this study, a SC cDNA, DCD, was cloned from Dryopteris crassirhizoma by homology-based RT-PCR. DCD contains a 2058-bp open reading frame that encodes a 685 amino acid polypeptide exhibiting 66% identity to the previously identified fern SC, ACH, and 35-40% identity to bacterial SCs. Heterologous expression of DCD in yeast established it to be a dammaradiene synthase affording dammara-18(28),21-diene, a tetracyclic triterpene hydrocarbon. Although neither this compound nor any derived metabolites have been previously reported from D. crassirhizoma, re-investigation of the leaflets demonstrated the presence of dammara-18(28),21-diene. DCD represents the first SC that produces a tetracyclic triterpene hydrocarbon. << Less

  Phytochemistry 69:2559-2564(2008) [PubMed] [EuropePMC]