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Title: Metabolic profiling reveals altered sugar and secondary metabolism in response to UGPase overexpression in Populus

Background: UDP-glucose pyrophopharylase (UGPase) is a sugar metabolizing enzyme (E.C. 2.7.7.9) that catalyzes a reversible reaction of UDP-glucose and pyrophosphate from glucose-1-phosphate and uridine triphosphate glucose. UDP-glucose is a key intermediate sugar that is channeled to multiple metabolic pathways. The functional role of UGPase in woody plants such as Populus is poorly understood. Results: We characterized the functional role of UGPase in Populus deltoides by overexpressing a native gene. Overexpression of the native gene resulted in increased leaf area and leaf-to-shoot biomass ratio but decreased shoot and root growth. Metabolomic analyses showed that manipulation of UGPase results in perturbations in primary as well as secondary metabolism resulting in reduced sugar and starch levels and increased phenolics such as caffeoyl- and feruloyl conjugates. While cellulose and lignin levels in the cell walls were not significantly altered, the syringyl-to-guaiacyl ratio was significantly reduced. Conclusions: These results demonstrate that UGPase plays a key role in the tightly coupled primary and secondary metabolic pathways and perturbation in its function results in pronounced effects on growth and metabolism outside of cell wall biosynthesis of Populus.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [1] ;  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
Publication Date:
OSTI Identifier:
1159413
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
BMC Plant Biology
Additional Journal Information:
Journal Volume: 14; Journal Issue: 265; Journal ID: ISSN 1471-2229
Publisher:
BioMed Central
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). BioEnergy Science Center (BESC)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES metabolic profiling; primary and secondary metabolism; cell wall; UGPase; Populus