An exploratory steady-state redox model of photosynthetic linear electron transport for use in complete modelling of photosynthesis for broad applications

Lianhong Gu, Bernard Grodzinski, Jimei Han, Telesphore Marie, Yong Jiang Zhang, Yang C. Song, Ying Sun

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

A photochemical model of photosynthetic electron transport (PET) is needed to integrate photophysics, photochemistry, and biochemistry to determine redox conditions of electron carriers and enzymes for plant stress assessment and mechanistically link sun-induced chlorophyll fluorescence to carbon assimilation for remotely sensing photosynthesis. Towards this goal, we derived photochemical equations governing the states and redox reactions of complexes and electron carriers along the PET chain. These equations allow the redox conditions of the mobile plastoquinone pool and the cytochrome b6f complex (Cyt) to be inferred with typical fluorometry. The equations agreed well with fluorometry measurements from diverse C3/C4 species across environments in the relationship between the PET rate and fraction of open photosystem II reaction centres. We found the oxidation of plastoquinol by Cyt is the bottleneck of PET, and genetically improving the oxidation of plastoquinol by Cyt may enhance the efficiency of PET and photosynthesis across species. Redox reactions and photochemical and biochemical interactions are highly redundant in their complex controls of PET. Although individual reaction rate constants cannot be resolved, they appear in parameter groups which can be collectively inferred with fluorometry measurements for broad applications. The new photochemical model developed enables advances in different fronts of photosynthesis research.

Original languageEnglish
Pages (from-to)1540-1561
Number of pages22
JournalPlant Cell and Environment
Volume46
Issue number5
DOIs
StatePublished - May 2023

Funding

The authors benefited from discussions on photosynthetic electron transport with Drs. Joe Berry, Albert Porcar-Castell and Xinyou Yin. Due to its difficulty, this manuscript in its numerous successive versions was reviewed by at least eight anonymous referees, which led to considerable improvement of the final manuscript. We are grateful to these colleagues. We also thank Dr. Jeff Wood and Ms. Jena Gu for comments on the manuscript. This research is supported by the US Department of Energy (DOE), Office of Science, Biological and Environmental Research Program. ORNL is managed by UT-Battelle, LLC, for DOE under contract DE-AC05-00OR22725. Y. S. and J. H. acknowledge support from NSF Macrosystem Biology (Award 1926488), USDA-NIFA Hatch Fund (1014740), and the Cornell Initiative for Digital Agriculture Research Innovation Fund. B. G. and T. M. acknowledge the support of the Ontario Ministry of Agriculture, Food and Rural Affairs for two OMAFRA-Alliance-T1 Awards (UofG2016-2732 & UG-T1-2021-100932). The authors benefited from discussions on photosynthetic electron transport with Drs. Joe Berry, Albert Porcar‐Castell and Xinyou Yin. Due to its difficulty, this manuscript in its numerous successive versions was reviewed by at least eight anonymous referees, which led to considerable improvement of the final manuscript. We are grateful to these colleagues. We also thank Dr. Jeff Wood and Ms. Jena Gu for comments on the manuscript. This research is supported by the US Department of Energy (DOE), Office of Science, Biological and Environmental Research Program. ORNL is managed by UT‐Battelle, LLC, for DOE under contract DE‐AC05‐00OR22725. Y. S. and J. H. acknowledge support from NSF Macrosystem Biology (Award 1926488), USDA‐NIFA Hatch Fund (1014740), and the Cornell Initiative for Digital Agriculture Research Innovation Fund. B. G. and T. M. acknowledge the support of the Ontario Ministry of Agriculture, Food and Rural Affairs for two OMAFRA‐Alliance‐T1 Awards (UofG2016‐2732 & UG‐T1‐2021‐100932).

Keywords

  • cytochrome bf complex
  • photosynthesis model
  • photosystems
  • plastoquinone
  • redox reactions

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