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Abstract Detail


Seed Biology

Rolletschek, Hardy [1], Wobus, Ulrich [2], Borisjuk, Ljudmilla [2].

Mechanisms for oxygen sensing and balancing in naturally hypoxic crop plant seeds.

Imposition of hypoxia leads to a rapid decrease in the availability of ATP, biosynthetic fluxes and affects gene expression. This is of high significance for plant seeds including the major crop species maize, soybean, oilseed rape, barley, wheat, pea and sunflower because their cellular environment is characteristically low in oxygen as we could recently demonstrate. Despite differences in morphology, photosynthetic capacity, respiration and various other parameters, it is quite astonishing that in all these types of seeds internal oxygen concentrations reach fairly similar, hypoxic levels ranging between 2-10 µM (in darkness). Such oxygen concentrations are still far from the Km-value of the mitochondrial cytochrome oxidase, implying that fine-tuning of oxygen occurs via another mechanisms, common to diverse plant species. We propose that [2-10 µM] represents a threshold level, enabling a sustainable metabolic activity but avoiding the risk of running into severe anoxia, finally causing cell death. Here, we applied a unique combination of methods including oxygen-sensitive microsensors, metabolite profiling, ATP-imaging via quantitative bioluminescence, stable isotope-based flux analysis and macroarray analysis, and analysed the mechanisms of the oxygen sensing and balancing system in seeds. We provide evidence that supports a model in which the NO/O2 ratio, as part of an oxygen sensing system, acts as a trigger tuning the tissue oxygen level.


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1 - Leibniz-Institut fr Pflanzengenetik und Kulturpflanzenforschung, Molecular Genetics, Corresnstr. 3, Gatersleben, 06466, Germany
2 - Leibniz-Institut fr Pflanzengenetik und Kulturpflanzenforschung, Molecular Genetics, Correnstr. 3, Gatersleben, 06466, Germany

Keywords:
hypoxia
crop.

Presentation Type: ASPB Minisymposium
Session: M07
Location: Continental C/Hilton
Date: Sunday, July 8th, 2007
Time: 5:25 PM
Number: M07004
Abstract ID:636


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