Open AccessProduction of indole alkaloids by metabolic engineering of the tryptophan pathway in rice
Author(s) -
Dubouzet Joseph G.,
Matsuda Fumio,
Ishihara Atsushi,
Miyagawa Hisashi,
Wakasa Kyo
Publication year - 2013
Publication title -
plant biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.525
H-Index - 115
eISSN - 1467-7652
pISSN - 1467-7644
DOI - 10.1111/pbi.12105
Subject(s) - tryptamine , tryptophan , indole test , biology , serotonin , mutant , tryptophan hydroxylase , aromatic l amino acid decarboxylase , biochemistry , metabolic engineering , gene , enzyme , amino acid , receptor , serotonergic
Summary 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 O s TDC , a putative tryptophan decarboxylase gene from rice, into an expression plasmid vector containing OASA 1 D , the feedback‐resistant anthranilate synthase alpha‐subunit mutant ( OASA 1 D ). Overexpression of OASA 1D has been reported to significantly increase Trp levels in rice. The co‐expression of Os TDC and OASA 1 D 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 OASA 1D . Metabolic profiling of the calli expressing Os TDC and OASA 1D revealed the accumulation of serotonin and serotonin‐derived indole compounds (potentially pharmacoactive β‐carbolines) that have not been reported from rice. Rice calli overexpressing OASA 1 D : OASA 1 D is a novel system for the production of significant amounts of pharmacologically useful indole alkaloids in rice.