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Re-evaluating the energy balance of the many routes of carbon flow through and from photorespiration.

Authors :
Walker B
Schmiege SC
Sharkey TD
Source :
Plant, cell & environment [Plant Cell Environ] 2024 Sep; Vol. 47 (9), pp. 3365-3374. Date of Electronic Publication: 2024 May 28.
Publication Year :
2024

Abstract

Photorespiration is an essential process related to photosynthesis that is initiated following the oxygenation reaction catalyzed by rubisco, the initial enzyme of the Calvin-Benson-Bassham cycle. This reaction produces an inhibitory intermediate that is recycled back into the Calvin-Benson-Bassham cycle by photorespiration which requires the use of energy and the release of a portion of the carbon as CO <subscript>2</subscript> . The energy use and CO <subscript>2</subscript> release of canonical photorespiration form a foundation for biochemical models used to describe and predict leaf carbon exchange and energy use (ATP and NAPDH). The ATP and NADPH demand of canonical photorespiration is thought to be different than that of the Calvin-Benson-Bassham cycle, requiring increased flexibility in the ratio of ATP and NADPH from the light reactions. Photorespiration requires many reactions across the chloroplasts, mitochondria and peroxisomes and involves many intermediates. Growing evidence indicates that these intermediates do not all stay in photorespiration as typically assumed and instead feed into other aspects of metabolism and leave as glycine, serine, and methylene-THF. Here we discuss how alternative flux through and from canonical photorespiration alters the ATP and NADPH requirements of metabolism following rubisco oxygenation using additional derivations of biochemical models of leaf photosynthesis and energetics. Using these new derivations, we determine that the ATP and NADPH demands of photorespiration are highly sensitive to alternative flux in ways that fundamentally changes how photorespiration contributes to the ratio of total ATP and NADPH demand. Specifically, alternative flows of carbon through photorespiration could reduce ATP and NADPH demand ratio to values below what is produced from linear electron transport.<br /> (© 2024 The Author(s). Plant, Cell & Environment published by John Wiley & Sons Ltd.)

Details

Language :
English
ISSN :
1365-3040
Volume :
47
Issue :
9
Database :
MEDLINE
Journal :
Plant, cell & environment
Publication Type :
Academic Journal
Accession number :
38804248
Full Text :
https://doi.org/10.1111/pce.14949