The effects of photosynthetic rate on respiration in light, starch/sucrose partitioning, and other metabolic fluxes within photosynthesis

Abstract In the future, plants may encounter increased light and elevated CO2 levels. How consequent alterations in photosynthetic rates will impact fluxes in photosynthetic carbon metabolism remains uncertain. Respiration in light (R L ) is pivotal in plant carbon balance and a key parameter in pho...

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Main Authors: Yuan Xu, Joshua A. M. Kaste, Sean E. Weise, Yair Shachar-Hill, Thomas D. Sharkey
Format: Article
Language:English
Published: Nature Portfolio 2025-03-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-025-88574-4
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author Yuan Xu
Joshua A. M. Kaste
Sean E. Weise
Yair Shachar-Hill
Thomas D. Sharkey
author_facet Yuan Xu
Joshua A. M. Kaste
Sean E. Weise
Yair Shachar-Hill
Thomas D. Sharkey
author_sort Yuan Xu
collection DOAJ
description Abstract In the future, plants may encounter increased light and elevated CO2 levels. How consequent alterations in photosynthetic rates will impact fluxes in photosynthetic carbon metabolism remains uncertain. Respiration in light (R L ) is pivotal in plant carbon balance and a key parameter in photosynthesis models. Understanding the dynamics of photosynthetic metabolism and R L under varying environmental conditions is essential for optimizing plant growth and agricultural productivity. However, measuring R L under high light and high CO2 (HLHC) conditions poses challenges using traditional gas exchange methods. In this study, we employed isotopically nonstationary metabolic flux analysis (INST-MFA) to estimate R L and investigate photosynthetic carbon flux, unveiling nuanced adjustments in Camelina sativa under HLHC. Despite numerous flux alterations in HLHC, R L remained stable. HLHC affects several factors influencing R L , such as starch and sucrose partitioning, v o /v c ratio, triose phosphate partitioning, and hexose kinase activity. Analysis of A/C i curve operational points reveals that HLHC’s major changes primarily stem from CO2 suppressing photorespiration. Integration of these fluxes into a simplified model predicts changes in CBC labeling under HLHC. This study extends our prior discovery that incomplete CBC labeling is due to unlabeled carbon reimported during R L , offering insights into manipulating labeling through adjustments in photosynthetic rates.
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spelling doaj-art-24faac85aa034d21bc7413d2978b53ab2025-08-20T02:56:06ZengNature PortfolioScientific Reports2045-23222025-03-0115111410.1038/s41598-025-88574-4The effects of photosynthetic rate on respiration in light, starch/sucrose partitioning, and other metabolic fluxes within photosynthesisYuan Xu0Joshua A. M. Kaste1Sean E. Weise2Yair Shachar-Hill3Thomas D. Sharkey4MSU-DOE Plant Research Laboratory, Michigan State UniversityDepartment of Biochemistry and Molecular Biology, Michigan State UniversityDepartment of Biochemistry and Molecular Biology, Michigan State UniversityDepartment of Plant Biology, Michigan State UniversityMSU-DOE Plant Research Laboratory, Michigan State UniversityAbstract In the future, plants may encounter increased light and elevated CO2 levels. How consequent alterations in photosynthetic rates will impact fluxes in photosynthetic carbon metabolism remains uncertain. Respiration in light (R L ) is pivotal in plant carbon balance and a key parameter in photosynthesis models. Understanding the dynamics of photosynthetic metabolism and R L under varying environmental conditions is essential for optimizing plant growth and agricultural productivity. However, measuring R L under high light and high CO2 (HLHC) conditions poses challenges using traditional gas exchange methods. In this study, we employed isotopically nonstationary metabolic flux analysis (INST-MFA) to estimate R L and investigate photosynthetic carbon flux, unveiling nuanced adjustments in Camelina sativa under HLHC. Despite numerous flux alterations in HLHC, R L remained stable. HLHC affects several factors influencing R L , such as starch and sucrose partitioning, v o /v c ratio, triose phosphate partitioning, and hexose kinase activity. Analysis of A/C i curve operational points reveals that HLHC’s major changes primarily stem from CO2 suppressing photorespiration. Integration of these fluxes into a simplified model predicts changes in CBC labeling under HLHC. This study extends our prior discovery that incomplete CBC labeling is due to unlabeled carbon reimported during R L , offering insights into manipulating labeling through adjustments in photosynthetic rates.https://doi.org/10.1038/s41598-025-88574-4Elevated CO2High lightMetabolic flux analysisPhotosynthesisPlant central metabolismStarch/sucrose partitioning
spellingShingle Yuan Xu
Joshua A. M. Kaste
Sean E. Weise
Yair Shachar-Hill
Thomas D. Sharkey
The effects of photosynthetic rate on respiration in light, starch/sucrose partitioning, and other metabolic fluxes within photosynthesis
Scientific Reports
Elevated CO2
High light
Metabolic flux analysis
Photosynthesis
Plant central metabolism
Starch/sucrose partitioning
title The effects of photosynthetic rate on respiration in light, starch/sucrose partitioning, and other metabolic fluxes within photosynthesis
title_full The effects of photosynthetic rate on respiration in light, starch/sucrose partitioning, and other metabolic fluxes within photosynthesis
title_fullStr The effects of photosynthetic rate on respiration in light, starch/sucrose partitioning, and other metabolic fluxes within photosynthesis
title_full_unstemmed The effects of photosynthetic rate on respiration in light, starch/sucrose partitioning, and other metabolic fluxes within photosynthesis
title_short The effects of photosynthetic rate on respiration in light, starch/sucrose partitioning, and other metabolic fluxes within photosynthesis
title_sort effects of photosynthetic rate on respiration in light starch sucrose partitioning and other metabolic fluxes within photosynthesis
topic Elevated CO2
High light
Metabolic flux analysis
Photosynthesis
Plant central metabolism
Starch/sucrose partitioning
url https://doi.org/10.1038/s41598-025-88574-4
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