1. Suppression of camptothecin biosynthetic genes results in metabolic modification of secondary products in hairy roots of Ophiorrhiza pumila.
- Author
-
Asano T, Kobayashi K, Kashihara E, Sudo H, Sasaki R, Iijima Y, Aoki K, Shibata D, Saito K, and Yamazaki M
- Subjects
- Aromatic-L-Amino-Acid Decarboxylases genetics, Aromatic-L-Amino-Acid Decarboxylases metabolism, Biocatalysis, Camptothecin chemistry, Cytochrome P-450 Enzyme System genetics, Cytochrome P-450 Enzyme System metabolism, Molecular Structure, Oxidoreductases Acting on CH-CH Group Donors genetics, Oxidoreductases Acting on CH-CH Group Donors metabolism, Plant Roots enzymology, RNA Interference, Rubiaceae enzymology, Aromatic Amino Acid Decarboxylase Inhibitors, Camptothecin biosynthesis, Cytochrome P-450 Enzyme Inhibitors, Oxidoreductases Acting on CH-CH Group Donors antagonists & inhibitors, Plant Roots metabolism, Rubiaceae metabolism
- Abstract
Camptothecin is a monoterpenoid indole alkaloid that exhibits anti-tumor activity. In Ophiorrhiza pumila, production of camptothecin and its related alkaloids was high in the hairy roots, but not in the cell suspension culture derived from hairy roots. To identify the intermediates in camptothecin biosynthesis, expression of genes encoding tryptophan decarboxylase (TDC) and secologanin synthase (SLS), the two enzymes catalyzing the early steps in camptothecin biosynthesis, were suppressed in the hairy roots of O. pumila by RNA interference (RNAi), and metabolite changes were investigated. In most TDC- and SLS-suppressed lines, accumulation of camptothecin and related alkaloids, strictosidine, strictosamide, pumiloside, and deoxypumiloside was reduced. The accumulation levels of secologanin exhibited a strong negative correlation with the expression level of TDC, and that of loganin exhibited a negative correlation with the expression level of SLS. Some hairy root-specific chromatographic peaks detected by liquid chromatography Fourier transform ion cyclotron resonance mass spectrometry (LC-FTICR-MS) exhibited positive or negative correlation with TDC expression, suggesting their possible involvement in camptothecin biosynthesis., (Copyright © 2012 Elsevier Ltd. All rights reserved.) more...
- Published
- 2013
- Full Text
- View/download PDF