title: The expression of 1-deoxy-D-xylulose synthase and geraniol-10-hydroxylase or anthranilate synthase increases terpenoid indole alkaloid accumulation in Catharanthus roseus hairy roots.
abstract: The terpenoid indole alkaloid (TIA) pathway in Catharanthus roseus produces two important anticancer drugs, vinblastine and vincristine, in very low yields. This study focuses on overexpressing several key genes in the upper part of the TIA pathway in order to increase flux toward downstream metabolites within hairy root cultures. Specifically, we constructed hairy root lines with inducible overexpression of 1-deoxy-D-xylulose synthase (DXS) or geraniol-10-hydroxylase (G10H). We also constructed hairy root lines with inducible expression of DXS and anthranilate synthase α subunit (ASA) or DXS and G10H. DXS overexpression resulted in a significant increase in ajmalicine by 67%, serpentine by 26% and lochnericine by 49% and a significant decrease in tabersonine by 66% and hörhammericine by 54%. Co-overexpression of DXS and G10H caused a significant increase in ajmalicine by 16%, lochnericine by 31% and tabersonine by 13%. Likewise, DXS and ASA overexpression displayed a significant increase in hörhammericine by 30%, lochnericine by 27% and tabersonine by 34%. These results point to the need for overexpressing multiple genes within the pathway to increase the flux toward vinblastine and vincristine.
authors.affiliation: Department of Bioengineering, Rice University, Houston, TX, USA.
authors.forename: Christie A M
authors.initials: CA
authors.lastname: Peebles
authors.forename: Guy W
authors.initials: GW
authors.lastname: Sander
authors.forename: Erik H
authors.initials: EH
authors.lastname: Hughes
authors.forename: Ryan
authors.initials: R
authors.lastname: Peacock
authors.forename: Jacqueline V
authors.initials: JV
authors.lastname: Shanks
authors.forename: Ka-Yiu
authors.initials: KY
authors.lastname: San
mesh_terms: D000878:Anthranilate Synthase / Q000096:biosynthesis* / Q000235:genetics; D030008:Catharanthus / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis* / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D018517:Plant Roots / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000378:metabolism; D046948:Secologanin Tryptamine Alkaloids / Q000378:metabolism*; D014166:Transferases / Q000096:biosynthesis* / Q000235:genetics; D014747:Vinblastine / Q000096:biosynthesis; D014750:Vincristine / Q000096:biosynthesis
chemical_list: D046948:Secologanin Tryptamine Alkaloids; D014750:Vincristine; D014747:Vinblastine; D003577:Cytochrome P-450 Enzyme System; C081675:geraniol 10-hydroxylase; D014166:Transferases; C109461:deoxyxylulose-5-phosphate synthase; D000878:Anthranilate Synthase