Open AccessReimport of carbon from cytosolic and vacuolar sugar pools into the Calvin–Benson cycle explains photosynthesis labeling anomalies
Author(s) -
Yuan Xu,
Thomas Wieloch,
Joshua A. M. Kaste,
Yair ShacharHill,
Thomas D. Sharkey
Publication year - 2022
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.2121531119
Subject(s) - photosynthesis , cytosol , pentose phosphate pathway , sugar , assimilation (phonology) , citric acid cycle , carbon assimilation , carbon cycle , sugar phosphates , metabolism , c4 photosynthesis , biochemistry , flux (metallurgy) , carbon fibers , chemistry , botany , biology , glycolysis , phosphate , ecology , ecosystem , enzyme , linguistics , philosophy , organic chemistry , composite number , materials science , composite material
Significance Photosynthesis metabolites are quickly labeled when13 CO2 is fed to leaves, but the time course of labeling reveals additional contributing processes involved in the metabolic dynamics of photosynthesis. The existence of three such processes is demonstrated, and a metabolic flux model is developed to explore and characterize them. The model is consistent with a slow return of carbon from cytosolic and vacuolar sugars into the Calvin–Benson cycle through the oxidative pentose phosphate pathway. Our results provide insight into how carbon assimilation is integrated into the metabolic network of photosynthetic cells with implications for global carbon fluxes.