Cyclic electron flow around photosystem I is essential for photosynthesis

@article{Munekage2004CyclicEF,
  title={Cyclic electron flow around photosystem I is essential for photosynthesis},
  author={Yuri N Munekage and Mihoko Hashimoto and Chikahiro Miyake and Ken-ichi Tomizawa and Tsuyoshi Endo and Masao Tasaka and Toshiharu Shikanai},
  journal={Nature},
  year={2004},
  volume={429},
  pages={579-582}
}
Photosynthesis provides at least two routes through which light energy can be used to generate a proton gradient across the thylakoid membrane of chloroplasts, which is subsequently used to synthesize ATP. In the first route, electrons released from water in photosystem II (PSII) are eventually transferred to NADP+ by way of photosystem I (PSI). This linear electron flow is driven by two photochemical reactions that function in series. The cytochrome b6f complex mediates electron transport… 
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References

SHOWING 1-10 OF 30 REFERENCES
Concerning a dual function of coupled cyclic electron transport in leaves.
TLDR
Coupled cyclic electron transport is assigned a role in the protection of leaves against photoinhibition in addition to its role in ATP synthesis and avoidance of overreduction of the electron transport chain is a prerequisite for the efficient protection of the photosynthetic apparatus against photo inactivation.
Cyclic electron transfer in plant leaf
  • P. Joliot, A. Joliot
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 2002
TLDR
It is proposed that the cyclic pathway operates within a supercomplex including one PSI, one cytochrome bf complex, one plastocyanin, and one ferredoxin, which induces the synthesis of ATP needed for the activation of the Benson–Calvin cycle.
Electron transport and photophosphorylation by Photosystem I in vivo in plants and cyanobacteria
TLDR
Under high light intensities where CO2 can limit photosynthesis, the proton gradient established by coupled cyclic electron transport can prevent over-reduction of the electron transport system by increasing thermal de-excitation in Photosystem II (Weis and Berry 1987).
Photosynthetic control of chloroplast gene expression
TLDR
Here it is shown that the redox state of plastoquinone also controls the rate of transcription of genes encoding reaction-centre apoproteins of photosystem I and photosystem II, and the stoichiometry between the two photosystems changes in a way that counteracts the inefficiency produced when either photosystem limits the rates of the other.
Electron acceptors in isolated intact spinach chloroplasts act hierarchically to prevent over-reduction and competition for electrons
TLDR
The different electron acceptors in the stroma are organized in a hierarchical manner; this allows electron flux towards CO2 and nitrite reduction to proceed without any competition for electrons, and any excess electrons to be taken by these additional non-assimilatory pathways.
Photosynthesis by Isolated Chloroplasts
TLDR
Evidence is given for the action of the photochemically generated assimilatory power on two phases of the reductive carbohydrate cycle in isolated chloroplasts: the carboxylative phase which includes the phosphorylation of ribulose monophosphate and the fixation of COZ, and the reduction of 3-phosphoglyceric acid and the formation of hexose phosphate.
Irrungen, Wirrungen? The Mehler reaction in relation to cyclic electron transport in C3 plants
  • U. Heber
  • Environmental Science
    Photosynthesis Research
  • 2004
TLDR
Cyclic electron flow acts in flexible relationship with the water–water cycle to control Photosystem II activity, which relieves the inhibition of cyclic electron transport, which is observed under excessive reduction of intersystem electron carriers.
THE WATER-WATER CYCLE IN CHLOROPLASTS: Scavenging of Active Oxygens and Dissipation of Excess Photons.
  • K. Asada
  • Environmental Science, Engineering
    Annual review of plant physiology and plant molecular biology
  • 1999
TLDR
Whenever the water-water cycle operates properly for scavenging of active oxygens in chloroplasts, it also effectively dissipates excess excitation energy under environmental stress.
Directed disruption of the tobacco ndhB gene impairs cyclic electron flow around photosystem I.
TLDR
Analysis of the transient increase in chlorophyll fluorescence after actinic light illumination and the redox kinetics of P700 suggest that the cyclic electron flow around PS I is impaired in the ndhB-deficient transformants, suggesting that the cycling of electrons aroundPS I mediated by ndh gene products is dispensable in tobacco under mild environmental conditions.
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