Evidence of a key role for photosynthetic oxygen release in oil storage in developing soybean seeds

Hardy Rolletschek, Ruslana Radchuk, Christian Klukas, Falk Schreiber, Ulrich Wobus, Ljudmilla Borisjuk

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71 Citations (Scopus)

Abstract

• Based on the topographical analysis of photosynthesis and oil storage, we propose in a companion paper that photosynthetic oxygen release plays a key role in the local energy state, storage metabolism and flux toward lipid biosynthesis in developing soybean seeds. To test this hypothesis, we combined topographical analysis of ATP gradients across tissues, microsensor quantifications of internal O2 levels, assays of energy balance, metabolite profiles and isotope-labelling studies. • Seeds show a marked degree of oxygen starvation in vivo (minimum O2 levels 0.1 kPa, ≈ 1.3μM), affecting ATP gradients, overall energy state, metabolite pools and storage activity. • Despite the low light availability, photosynthesis supplies significant amounts of oxygen to the hypoxic seed tissue. This is followed by an increase in local ATP levels, most prominently within the lipid-synthesizing (inner) regions of the embryo. Concomitantly, partitioning of 14C-sucrose to lipids is increased, suggesting higher rates of lipid biosynthesis. • It is concluded that both respiratory and biosynthetic fluxes are dynamically adjusted to photosynthetic oxygen supply.

Original languageEnglish
Pages (from-to)777-786
Number of pages10
JournalNew Phytologist
Volume167
Issue number3
DOIs
Publication statusPublished - Sep 2005
Externally publishedYes

Keywords

  • ATP imaging
  • Energy state
  • Hypoxia
  • Lipid biosynthesis
  • Metabolite profiling
  • Microsensor
  • Photosynthesis
  • Seed development

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