Carbon metabolism in leaves of transgenic tobacco (Nicotiana tabacum L.) containing elevated fructose 2,6-bisphosphate levels.
The aim of this work was to investigate the role of fructose 2,6-bisphosphate (Fru 2,6-P2) during photosynthesis. The level of Fru 2,6-P2 in tobacco plants was elevated by the introduction of a modified mammalian gene encoding 6-phosphofructo-2-kinase (6-PF-2-K). Estimates of the metabolite control coefficient (C) for Fru 2,6-P2 levels in response to increased 6-PF-2-K activity, suggest that small increases in 6-PF-2-K activity have little effect upon steady-state Fru 2,6-P2 levels (C = +0.08 for a 0-58% increase in 6-PF-2-K activity). However, larger changes resulted in dramatic rises in Fru 2,6-P2 levels (C = +3.35 for 206-268% increase in 6-PF-2-K activity). Transgenic plants contained Fru 2,6-P2 levels in the dark that ranged from 104 to 230% of the level in wild-type tobacco. Plants with altered levels of Fru 2,6-P2 were used to determine the effects of this signal metabolite upon carbohydrate metabolism during the initial phase of the light period. Here we provide direct evidence that Fru 2,6-P2 contributes to the regulation of carbon partitioning in tobacco leaves by inhibiting sucrose synthesis.
Scott
P
P
Department of Plant Sciences, University of Oxford, UK.
Lange
A J
AJ
Pilkis
S J
SJ
Kruger
N J
NJ
D000818:Animals; D001483:Base Sequence; D050260:Carbohydrate Metabolism; D002244:Carbon / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D005635:Fructosediphosphates / Q000378:metabolism*; D017343:Genes, Plant; D008099:Liver / Q000201:enzymology; D008969:Molecular Sequence Data; D025481:Phosphofructokinase-2; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D051381:Rats; D014026:Nicotiana / Q000235:genetics* / Q000378:metabolism*
D017931:DNA Primers; D005635:Fructosediphosphates; D002244:Carbon; C027652:fructose 2,6-diphosphate; D017853:Phosphotransferases (Alcohol Group Acceptor); D025481:Phosphofructokinase-2