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The biochemical and molecular basis for photosynthetic acclimation to elevated atmospheric CO 2
Author(s) -
MOORE B. D.,
CHENG S.H.,
SIMS D.,
SEEMANN J. R.
Publication year - 1999
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 - 10.1046/j.1365-3040.1999.00432.x
Subject(s) - rubisco , biology , photosynthesis , biochemistry , protein subunit , photosystem i , gene , pyruvate carboxylase , hexokinase , photosystem ii , metabolism , enzyme , glycolysis
Amax , maximum CO 2 assimilation rate
CAB , genes encoding chlorophyll a / b binding proteins
C i , intercellular CO 2 concentration
PGK , the gene encoding 3‐phosphoglycerate kinase
PRK , the gene encoding phosphoribulokinase
PSAB , the gene encoding the 83 kDa apoprotein of the PSI reaction centre
PSBA, the gene encoding the D1 protein of photosystem II
RBCS , genes encoding the Rubisco small subunit protein
RBCL , the gene encoding the Rubisco large subunit protein
Rubisco, ribulose‐1,5‐bisphosphate carboxylase/ oxygenase
SBP , the gene encoding sedoheptulose‐1,5‐bisphosphatase
There have been many recent exciting advances in our understanding of the cellular processes that underlie photosynthetic acclimation to rising atmospheric CO 2 concentration. Of particular interest have been the molecular processes that modulate photosynthetic gene expression in response to elevated CO 2 and the biochemical processes that link changes in atmospheric CO 2 concentration to the production of a metabolic signal. Central to this acclimation response is a reduction in ribulose‐1,5‐bisphosphate carboxylase/oxygenase (Rubisco) protein content. Studies indicate that this reduction results from species‐dependent variation in the differential use and temporal control of molecular processes. We present a model for the control of Rubisco protein accumulation that emphasizes the role of subunit message translation as well as the abundance of subunit messages as components of the acclimation response. Many studies indicate that photosynthetic acclimation to elevated CO 2 results from adjustments in leaf carbohydrate signalling. The repression of photosynthetic gene expression is considered to occur primarily by hexokinase functioning as a hexose flux sensor that ultimately affects transcription. Leaf hexoses may be produced as potential sources of signals primarily by sucrose cycling and secondarily by starch hydrolysis. An increased rate of sucrose cycling is suggested to occur at elevated CO 2 by enhanced provision of sucrose to leaf acid invertases. Additionally, sink limitations that accentuate photosynthetic acclimation may result from a relative decrease in the export of leaf sucrose and subsequent increase in cellular sucrose levels and sucrose cycling.