title: Dynamic metabolic flux analysis of plant cell wall synthesis.
abstract: The regulation of plant cell wall synthesis pathways remains poorly understood. This has become a bottleneck in designing bioenergy crops. The goal of this study was to analyze the regulation of plant cell wall precursor metabolism using metabolic flux analysis based on dynamic labeling experiments. Arabidopsis T87 cells were cultured heterotrophically with (13)C labeled sucrose. The time course of ¹³C labeling patterns in cell wall precursors and related sugar phosphates was monitored using liquid chromatography tandem mass spectrometry until steady state labeling was reached. A kinetic model based on mass action reaction mechanisms was developed to simulate the carbon flow in the cell wall synthesis network. The kinetic parameters of the model were determined by fitting the model to the labeling time course data, cell wall composition, and synthesis rates. A metabolic control analysis was performed to predict metabolic regulations that may improve plant biomass composition for biofuel production. Our results describe the routes and rates of carbon flow from sucrose to cell wall precursors. We found that sucrose invertase is responsible for the entry of sucrose into metabolism and UDP-glucose-4-epimerase plays a dominant role in UDP-Gal synthesis in heterotrophic Aradidopsis cells under aerobic conditions. We also predicted reactions that exert strong regulatory influence over carbon flow to cell wall synthesis and its composition.
authors: Plant Biology Department and Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI 48824, USA. xwchen@msu.edu
authors: Xuewen
authors: X
authors: Chen
authors: Ana P
authors: AP
authors: Alonso
authors: Yair
authors: Y
authors: Shachar-Hill
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000378:metabolism*; D001693:Biological Transport, Active / Q000187:drug effects / Q000502:physiology; D002247:Carbon Isotopes / Q000378:metabolism / Q000494:pharmacology; D002473:Cell Wall / Q000378:metabolism*; D007553:Isotope Labeling; D008954:Models, Biological; D059828:Plant Cells / Q000378:metabolism*; D013395:Sucrose / Q000378:metabolism / Q000494:pharmacology; D013549:Sweetening Agents / Q000378:metabolism / Q000494:pharmacology
chemical_list: D002247:Carbon Isotopes; D013549:Sweetening Agents; D013395:Sucrose