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Metabolic flux maps comparing the effect of temperature on protein and oil biosynthesis in developing soybean cotyledons
Author(s) -
IYER VIDYA V.,
SRIRAM GANESH,
FULTON D. BRUCE,
ZHOU RUILIAN,
WESTGATE MARK E.,
SHANKS JACQUELINE. V.
Publication year - 2008
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2008.01781.x
Subject(s) - phosphoenolpyruvate carboxylase , malic enzyme , flux (metallurgy) , metabolic flux analysis , sucrose , biochemistry , pyruvate carboxylase , phosphoenolpyruvate carboxykinase , pentose phosphate pathway , metabolism , biology , metabolic pathway , cytosol , chemistry , enzyme , glycolysis , dehydrogenase , organic chemistry
Metabolic flux maps developed from 13 C metabolic flux analysis ( 13 C MFA) are effective tools for assessing the response of biological systems to genetic or environmental perturbations, and for identifying possible metabolic engineering targets. Experimental treatments were designed to distinguish between temperature effects prior to, and during incubation in vitro , on primary metabolism in developing soybeans. Biomass accumulation increased with temperature as did carbon partitioning into lipids. The flux through the plastidic oxidative pentose phosphate pathway (pgl P ) relative to sucrose intake remained fairly constant [∼56% (±24%)] when cotyledons were transferred from an optimum growth temperature to varying temperatures in in vitro culture, signifying a rigid node under these conditions. However, pgl P flux ranged from 57 to 77% of sucrose intake when growth temperature in planta varied and were cultured in vitro at the same temperature (as the plant), indicating a flexible node for this case. The carbon flux through the anaplerotic reactions catalysed by plastidic malic enzyme (me P ), cytosolic phosphoenolpyruvate (PEP) carboxylase and the malate (Mal) transporter from the cytosol to mitochondrion varied dramatically with temperature and had a direct influence on the carbon partitioning into protein and oil from the plastidic pyruvate (Pyr) pool. These results of the in vitro culture indicate that temperature during early stages of development has a dominant effect on establishing capacity for flux through certain components of central carbon metabolism.