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          Institute: MPI für molekulare Pflanzenphysiologie     Collection: Publikationen Pflanzenphysiologie     Display Documents

ID: 228564.0, MPI für molekulare Pflanzenphysiologie / Publikationen Pflanzenphysiologie
Heterologous expression of a ketohexokinase in potato plants leads to inhibited rates of photosynthesis, severe growth retardation and abnormal leaf development
Authors:Geigenberger, P.; Regierer, B.; Lytovchenko, A.; Leisse, A.; Schauer, N.; Springer, F.; Kossmann, J.; Fernie, A. R.
Date of Publication (YYYY-MM-DD):2004-02
Title of Journal:Planta
Journal Abbrev.:Planta
Issue / Number:4
Start Page:569
End Page:578
Review Status:not specified
Audience:Not Specified
Abstract / Description:In the present paper we investigated the effect of heterologous expression of a rat liver ketohexokinase in potato (Solanum tuberosum L.) plants with the aim of investigating the role of fructose 1-phosphate in plant metabolism. Plants were generated that contained appreciable activity of ketohexokinase but did not accumulate fructose 1-phosphate. They were, however, characterised by a severe growth retardation and abnormal leaf development. Studies of (CO2)-C-14 assimilation and metabolism, and of the levels of photosynthetic pigments, revealed that these lines exhibited restricted photosynthesis. Despite this fact, the levels of starch and soluble sugars remained relatively constant. Analysis of intermediates of starch and sucrose biosynthesis revealed large increases in the triose phosphate and fructose 1,6-bisphosphate pools but relatively unaltered levels of inorganic phosphate and 3-phosphoglycerate, and these lines were also characterised by an accumulation of glyceraldehyde. The transformants neither displayed consistent changes in the activities of Calvin cycle enzymes nor in enzymes of sucrose synthesis but displayed a metabolic profile partially reminiscent of that brought about by end-product limitation, but most likely caused by an inhibition of photosynthesis brought about by the accumulation of glyceraldehyde. Analysis of the metabolite contents in lamina and vein fractions of the leaf, and of the enzymes of carbohydrate oxidation indicate that the phloem-enriched veins of ketohexokinase-expressing leaves tend toward hypoxia and indicate a problem of phloem transport.
Free Keywords:fructose 1-phosphate
; hypoxia
; ketohexokinase
; photosynthesis
; solanum
; yeast-derived invertase
; triose-phosphate translocator
; low internal oxygen
; antisense repression
; sucrose degradation
; starch synthesis
; tobacco plants
; metabolism
; tubers
; leaves
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für molekulare Pflanzenphysiologie/Molekulare Physiologie/AG Willmitzer/Fernie
MPI für molekulare Pflanzenphysiologie/Metabolische Netzwerke/AG Geigenberger
External Affiliations:Max Planck Inst Mol Pflanzenphysiol, Muhlenberg 1, D-14476 Golm, Germany
Max Planck Inst Mol Pflanzenphysiol, D-14476 Golm, Germany
Max Planck Inst Mol Genet, D-14195 Berlin, Germany
Risoe Natl Lab, Riso, Denmark
Identifiers:ISI:000188933000008 [ID No:1]
ISI:000188933000008 [ID No:2]
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