title: Production of indole alkaloids by metabolic engineering of the tryptophan pathway in rice.
abstract: Tryptophan decarboxylase (TDC) converts tryptophan (Trp) into tryptamine, consequently increasing the metabolic flow of tryptophan derivatives into the production of secondary metabolites such as indole alkaloids. We inserted an expression cassette containing OsTDC, a putative tryptophan decarboxylase gene from rice, into an expression plasmid vector containing OASA1D, the feedback-resistant anthranilate synthase alpha-subunit mutant (OASA1D). Overexpression of OASA1D has been reported to significantly increase Trp levels in rice. The co-expression of OsTDC and OASA1D in rice calli led to almost complete depletion of the Trp pool and a consequent increase in the tryptamine pool. This indicates that TDC inactivity is a contributory factor for the accumulation of Trp in rice transgenics overexpressing OASA1D. Metabolic profiling of the calli expressing OsTDC and OASA1D revealed the accumulation of serotonin and serotonin-derived indole compounds (potentially pharmacoactive β-carbolines) that have not been reported from rice. Rice calli overexpressing OASA1D:OASA1D is a novel system for the production of significant amounts of pharmacologically useful indole alkaloids in rice.
authors: JST/CREST Plant Functions and Their Control, Japan Science and Technology Agency, Tokyo, Japan; Biotransformation Team, Scion Research, Rotorua, New Zealand.
authors: Joseph G
authors: JG
authors: Dubouzet
authors: Fumio
authors: F
authors: Matsuda
authors: Atsushi
authors: A
authors: Ishihara
authors: Hisashi
authors: H
authors: Miyagawa
authors: Kyo
authors: K
authors: Wakasa
mesh_terms: D000878:Anthranilate Synthase / Q000235:genetics / Q000378:metabolism; D001142:Aromatic-L-Amino-Acid Decarboxylases / Q000235:genetics / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D026121:Indole Alkaloids / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D060847:Metabolic Engineering; D053858:Metabolic Networks and Pathways; D055442:Metabolome; D012275:Oryza / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D036226:Seedlings / Q000235:genetics / Q000378:metabolism; D012701:Serotonin / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D014363:Tryptamines / Q000378:metabolism; D014364:Tryptophan / Q000378:metabolism*
chemical_list: D026121:Indole Alkaloids; D010940:Plant Proteins; D014363:Tryptamines; D012701:Serotonin; C030820:tryptamine; D014364:Tryptophan; D001142:Aromatic-L-Amino-Acid Decarboxylases; D000878:Anthranilate Synthase
keywords: anthranilate synthase; serotonin; tryptamine; tryptophan decarboxylase; β-carboline