Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

The PSI-H subunit of photosystem I is essential for state transitions in plant photosynthesis


Photosynthesis in plants involves two photosystems responsible for converting light energy into redox processes. The photosystems, PSI and PSII, operate largely in series, and therefore their excitation must be balanced in order to optimize photosynthetic performance1. When plants are exposed to illumination favouring either PSII or PSI they can redistribute excitation towards the light-limited photosystem. Long-term changes in illumination lead to changes in photosystem stoichiometry2,3. In contrast, state transition is a dynamic mechanism that enables plants to respond rapidly to changes in illumination. When PSII is favoured (state 2), the redox conditions in the thylakoids change and result in activation of a protein kinase4,5,6. The kinase phosphorylates the main light-harvesting complex (LHCII) and the mobile antenna complex is detached from PSII. It has not been clear if attachment of LHCII to PSI in state 2 is important in state transitions. Here we show that in the absence of a specific PSI subunit, PSI-H, LHCII cannot transfer energy to PSI, and state transitions are impaired.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Measurements of transitions between state 1 and state 2.
Figure 2: In vitro phosphorylation of LHCII.
Figure 3: Reversible phosphorylation of LHCII in vivo.
Figure 4: Light saturation curve for P700 oxidation in intact leaves.


  1. 1

    Niyogi, K. K. Photoprotection revisited: genetic and molecular approaches. Annu. Rev. Plant Physiol. Plant Mol. Biol. 50, 333–359 (1999).

    CAS  Article  Google Scholar 

  2. 2

    Pfannschmidt, T., Nilsson, A. & Allen, J. F. Photosynthetic control of chloroplast gene expression. Nature 397, 625–628 (1999).

    ADS  CAS  Article  Google Scholar 

  3. 3

    Walters, R. G. & Horton, P. Acclimation of Arabidopsis thaliana to the light environment: changes in photosynthetic apparatus. Planta 195, 248–256 (1994).

    CAS  Article  Google Scholar 

  4. 4

    Allen, J. F. & Nilsson, A. Redox signalling and the structural basis of regulation of photosynthesis by protein phosphorylation. Physiol. Plant. 100, 863–868 (1997).

    CAS  Article  Google Scholar 

  5. 5

    Gal, A., Zer, H. & Ohad, I. Redox-controlled thylakoid protein phosphorylation. News and views. Physiol. Plant. 100, 869–885 (1997).

    CAS  Article  Google Scholar 

  6. 6

    Zito, F. et al. The Qo site of cytochrome b6 f complexes controls the activation of the LHCII kinase. EMBO J. 18, 2961–2969 (1999).

    CAS  Article  Google Scholar 

  7. 7

    Scheller, H. V., Naver, H. & Møller, B. L. Molecular aspects of photosystem I. Physiol. Plant. 100, 842–851 (1997).

    CAS  Article  Google Scholar 

  8. 8

    Jansson, S. A guide to the Lhc genes and their relatives in Arabidopsis. Trends Plant Sci. 4, 236–240 (1999).

    CAS  Article  Google Scholar 

  9. 9

    Horton, P. Are grana necessary for regulation of light harvesting? Aust. J. Plant Physiol. 26, 659–669 (1999).

    CAS  Google Scholar 

  10. 10

    Naver, H., Haldrup, A. & Scheller, H. V. Cosuppression of photosystem I subunit PSI-H in Arabidopsis thaliana. J. Biol. Chem. 274, 10784–10789 (1999).

    CAS  Article  Google Scholar 

  11. 11

    Haldrup, A., Naver, H. & Scheller, H. V. The interaction between plastocyanin and photosystem I is inefficient in transgenic Arabidopsis plants lacking the PSI-N subunit of photosystem I. Plant J. 17, 689–698 (1999).

    CAS  Article  Google Scholar 

  12. 12

    Jensen, P. E., Gilpin, M., Knoetzel, J. & Scheller, H. V. The PSI-K subunit of photosystem I is involved in the interaction between light harvesting complex I-680 and the photosystem I reaction center core. J. Biol. Chem. 275, 24701–24708 (2000).

    CAS  Article  Google Scholar 

  13. 13

    Allen, J. F., Bennett, J., Steinback, K. E. & Arntzen, C. J. Chloroplast protein phosphorylation couples plastoquinone redox state to distribution of excitation energy between photosystems. Nature 291, 25–29 (1981).

    ADS  CAS  Article  Google Scholar 

  14. 14

    Bassi, R. Spectral properties and polypeptide composition of the chlorophyll-proteins from thylakoids of granal and agranal chloroplasts of maize (Zea mays L.). Carlsberg Res. Commun. 50, 127–143 (1985).

    CAS  Article  Google Scholar 

  15. 15

    Bassi, R., Machold, O. & Simpson, D. Chlorophyll-proteins of two photosystem I preparations from maize. Carlsberg Res. Commun. 50, 145–162 (1985).

    CAS  Article  Google Scholar 

  16. 16

    Knoetzel, J. & Simpson, D. Expression and organisation of antenna proteins in the light- and temperature-sensitive barley mutant chlorina-104. Planta 185, 111–123 (1991).

    CAS  Article  Google Scholar 

  17. 17

    Boekema, E. J. et al. Green plant photosystem I binds light-harvesting complex I on one side of the complex. Biochemistry (in the press).

  18. 18

    Fromme, P. Structure and function of photosystem I. Curr. Opin. Struct. Biol. 6, 473–484 (1996).

    CAS  Article  Google Scholar 

  19. 19

    Jansson, S., Andersen, B. & Scheller, H. V. Nearest-neighbor analysis of higher-plant photosystem I holocomplex. Plant Physiol. 112, 409–420 (1996).

    CAS  Article  Google Scholar 

  20. 20

    Samson, G. & Bruce, D. Complementary changes in absorption cross-sections of photosystems I and photosystems II due to phosphorylation and Mg2+-depletion in spinach thylakoids. Biochim. Biophys. Acta 1232, 21–26 (1995).

    Article  Google Scholar 

  21. 21

    Kruse, O., Nixon, P. J., Schmid, G. H. & Mullineaux, C. W. Isolation of state transition mutants of Chlamydomonas reinhardtii by fluorescence video imaging. Photosynth. Res. 61, 43–51 (1999).

    CAS  Article  Google Scholar 

  22. 22

    Fleischmann, M. M. et al. Isolation and characterization of photoautotrophic mutants of Chlamydomonas reinhardtii deficient in state transition. J. Biol. Chem. 274, 30987–30994 (1999).

    CAS  Article  Google Scholar 

  23. 23

    Kjær, B. & Scheller, H. V. An isolated reaction center complex from the green sulfur bacterium Chlorobium vibrioforme can photoreduce ferredoxin at high rates. Photosynth. Res. 47, 33–39 (1996).

    Article  Google Scholar 

  24. 24

    Steinback, K. E., Bose, S. & Kyle, D. J. Phosphorylation of the light-harvesting chlorophyll-protein regulates excitation energy distribution between photosystem II and photosystem I. Arch. Biochem. Biophys. 216, 356–361 (1982).

    CAS  Article  Google Scholar 

Download references


We thank M. Jensen for technical assistance, B.L. Møller for discussions, and The Danish National Research Foundation for financial support.

Author information



Corresponding author

Correspondence to Henrik Vibe Scheller.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Lunde, C., Jensen, P., Haldrup, A. et al. The PSI-H subunit of photosystem I is essential for state transitions in plant photosynthesis. Nature 408, 613–615 (2000).

Download citation

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing