Metabolic changes of Brassica rapa transformed with a bacterial isochorismate synthase gene.
Metabolome analysis by 1-dimensional proton nuclear magnetic resonance (¹H NMR) coupled with multivariate data analysis was carried out in Brassica rapa plants transformed with a gene encoding bacterial isochorismate synthase (ICS). Partial least square-discrimination analysis (PLS-DA) on selected signals suggested that the resonances that were dominant in the transgenic plants corresponded to a glucosinolate (neoglucobrassicin), phenylpropanoids (sinapoyl malate, feruloyl malate, caffeoyl malate), organic acids (succinic acid and fumaric acid) and sugars (α- and β-glucose). In contrast, amino acids alanine threonine, valine, leucine were dominant in the untransformed controls. In addition, HPLC data showed that the transgenic plant accumulated salicylic acid (SA) at significantly higher levels than the control plants, whereas the phylloquinone levels were not affected. The results suggest that the expression of the bacterial isochorismate synthase gene in B. rapa does not affect fluxes into pathways to other groups of secondary metabolites through competition for the same precursor. On the contrary, the biosynthesis of isochorismate-derived products (SA) seems to induce the competitive pathways via phenylalanine (phenylpropanoids) and tryptophan (IAA and indole glucosinolates).
Simoh
Sanimah
S
Division of Pharmacognosy, Section Metabolomics, Institute of Biology, Leiden University, Leiden, The Netherlands.
Linthorst
Huub J M
HJ
Lefeber
Alfons W M
AW
Erkelens
Cornelis
C
Kim
Hye Kyong
HK
Choi
Young Hae
YH
Verpoorte
Robert
R
D001426:Bacterial Proteins / Q000235:genetics*; D029741:Brassica rapa / Q000235:genetics / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D019751:Intramolecular Transferases / Q000235:genetics / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008954:Models, Biological; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism*; D014170:Transformation, Genetic
D001426:Bacterial Proteins; D019751:Intramolecular Transferases; C058486:isochorismate synthase