Metabolic flux analysis in plants using dynamic labeling technique: Application to tryptophan biosynthesis in cultured rice cells

Mizutani, Fumio; Wakasa, K.; Miyagawa, Hisashi

doi:10.1016/j.phytochem.2007.03.031

Cited by 19 publications

(9 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These findings prove that feedback sensitivity is crucial for the control of Trp content in plants. Matsuda et al (2007) directly detected the enhanced metabolic flux in OASA1D transgeninc rice cells by dynamic labeling technique.…”

Section: Resultsmentioning

confidence: 99%

Metabolic engineering of the tryptophan and phenylalanine biosynthetic pathways in rice

Wakasa

Ishihara

2009

Plant Biotechnology

Self Cite

View full text Add to dashboard Cite

Tryptophan (Trp) and phenylalanine (Phe) are essential aromatic amino acids that animals cannot synthesize and are dependent on plants for their supply. In particular, Trp contributes to the nutritional quality of plant-based foods, and, along with lysine, methionine and threonine, it is used to supplement animal feeds. The other aromatic amino acids, Phe and tyrosine (Tyr), are used for the production of the low-calorie sweetener aspartame and the anti-Parkinson's disease drug L-dopa, respectively. The biosynthetic pathways for aromatic amino acids and their regulation have been extensively explored in bacteria because of their utility in the food and drug industry. In plants, aromatic amino acids are the precursors for a large variety of secondary metabolites including indole alkaloids, phenylpropanoids, flavonoids, and the phenolic polymer, lignin. One of plant growth regulators, indole-3-acetic acid (IAA), has also been shown to be biosynthesized from Trp. Thus, aromatic amino acids also play important roles in plant defense and development.In bacteria, fungi and plants, the three aromatic amino acids, Trp, Phe and Tyr, are synthesized from a common precursor, chorismate that originates from the shikimate pathway ( Figure 1). In bacteria, this pathway is almost exclusively used to produce aromatic amino acids for protein synthesis but, in higher plants, this pathway leads to the production of numerous aromatic secondary metabolites. The importance of this pathway in plants is indicated by the fact that about 20% of the carbon fixed by photosynthesis flow through this pathway. These facts strongly suggest that the modification of the shikimate and its derivative (or downstream) pathways may lead to dramatic changes in secondary metabolism. The enzymatic reactions in the biosynthetic pathway for aromatic amino acids seem to be identical in prokaryotes and eukaryotes but they apparently differ in the regulatory mechanisms for these pathways. For example, 3-deoxy-D-arabino-heptulosonate 7-phosphate (DAHP) synthase, the enzyme that catalyzes the first reaction in the shikimate pathway, is not feedback inhibited by any of the aromatic amino acids in plants, but, each of the three DAHP synthase isoenzymes are Abstract Aromatic amino acids function as building blocks of proteins and as precursors for secondary metabolism. To obtain plants that accumulate tryptophan (Trp) and phenylalanine (Phe), we modified the biosynthetic pathways for these amino acids in rice and dicot species. By introducing a gene encoding a feedback-insensitive anthranilate synthase (AS) alpha subunit, we successfully obtained transgenic plants that over-accumulated Trp. In addition, we found mutant calli that accumulated Phe and Trp at high concentrations. The causal gene (mtr1-D) encoded an arogenate dehydratase (ADT)/prephenate dehydratase (PDT) that catalyzes the final reaction in Phe biosynthesis. The wild-type enzyme was sensitive to feedback inhibition by Phe, but the mutant enzyme encoded by mtr1-D was relatively insensitive. Further, ...

show abstract

Section: Resultsmentioning

confidence: 99%

Metabolic engineering of the tryptophan and phenylalanine biosynthetic pathways in rice

Wakasa

Ishihara

2009

Plant Biotechnology

Self Cite

View full text Add to dashboard Cite

show abstract

“…These and other kinetic flux analysis studies, of which a substantial proportion are aimed at understanding the regulation of photosynthesis, have been reviewed elsewhere (81,87). Additional studies analyzing tryptophan biosynthesis in cultured rice cells (62) and describing the kinetics of label distribution through central metabolism in heterotrophically growing Arabidopsis cells (10) have appeared since then.…”

Section: Figurementioning

confidence: 99%

Metabolic Flux Analysis in Plants: From Intelligent Design to Rational Engineering

Libourel

Shachar‐Hill

2008

Annu. Rev. Plant Biol.

View full text Add to dashboard Cite

Metabolic flux analysis (MFA) is a rapidly developing field concerned with the quantification and understanding of metabolism at the systems level. The application of MFA has produced detailed maps of flow through metabolic networks of a range of plant systems. These maps represent detailed metabolic phenotypes, contribute significantly to our understanding of metabolism in plants, and have led to the discovery of new metabolic routes. The presentation of thorough statistical evaluation with current flux maps has set a new standard for the quality of quantitative flux studies. In microbial systems, powerful methods have been developed for the reconstruction of metabolic networks from genomic and transcriptomic data, pathway analysis, and predictive modeling. This review brings together the recent developments in quantitative MFA and predictive modeling. The application of predictive tools to high quality flux maps in particular promises to be important in the rational metabolic engineering of plants.

show abstract

“…MFA using isotopic transient data is more often applied in eukaryotic systems as it is not so easy to avoid compartmentalization and bi-directional exchange with large metabolic pools. However, since the nature of many of these dynamic processes has yet to be elucidated, MFA using isotopic transient data has been performed mostly on small linear branches of the metabolic networks without accounting for global dynamic behavior [ 15 ]. There are a few exceptions however, notably Heinzle et al [ 16 ] who used a combination of kinetic network modeling and simulation to calculate metabolic fluxes in a secondary metabolic network in potato ( Solanum tuberosum ).…”

Section: Dynamic Mfa In Eukaryotic Systemsmentioning

confidence: 99%

Bidirectionality and Compartmentation of Metabolic Fluxes Are Revealed in the Dynamics of Isotopomer Networks

Schryer

Peterson

Paalme

et al. 2009

IJMS

View full text Add to dashboard Cite

Isotope labeling is one of the few methods of revealing the in vivo bidirectionality and compartmentalization of metabolic fluxes within metabolic networks. We argue that a shift from steady state to dynamic isotopomer analysis is required to deal with these cellular complexities and provide a review of dynamic studies of compartmentalized energy fluxes in eukaryotic cells including cardiac muscle, plants, and astrocytes. Knowledge of complex metabolic behaviour on a molecular level is prerequisite for the intelligent design of genetically modified organisms able to realize their potential of revolutionizing food, energy, and pharmaceutical production. We describe techniques to explore the bidirectionality and compartmentalization of metabolic fluxes using information contained in the isotopic transient, and discuss the integration of kinetic models with MFA. The flux parameters of an example metabolic network were optimized to examine the compartmentalization of metabolites and and the bidirectionality of fluxes in the TCA cycle of Saccharomyces uvarum for steady-state respiratory growth.

show abstract

Metabolic flux analysis in plants using dynamic labeling technique: Application to tryptophan biosynthesis in cultured rice cells

Cited by 19 publications

References 56 publications

Metabolic engineering of the tryptophan and phenylalanine biosynthetic pathways in rice

Metabolic engineering of the tryptophan and phenylalanine biosynthetic pathways in rice

Metabolic Flux Analysis in Plants: From Intelligent Design to Rational Engineering

Bidirectionality and Compartmentation of Metabolic Fluxes Are Revealed in the Dynamics of Isotopomer Networks

Contact Info

Product

Resources

About