Physiological and evolutionary implications of tetrameric photosystem I in cyanobacteria

Li, M., Calteau, A., Semchonok, D. A., Witt, T. A., Nguyen, J. T., Sassoon, N., Boekema, E. J., Whitelegge, J., Gugger, M. & Bruce, B. D., Dec-2019, In : Nature Plants. 5, 12, p. 1309-1319 11 p.

Research output: Contribution to journalArticleAcademicpeer-review

  • Meng Li
  • Alexandra Calteau
  • Dmitry A. Semchonok
  • Thomas A. Witt
  • Jonathan T. Nguyen
  • Nathalie Sassoon
  • Egbert J. Boekema
  • Julian Whitelegge
  • Muriel Gugger
  • Barry D Bruce

Photosystem I (PSI) is present as trimeric complexes in most characterized cyanobacteria and as monomers in plants and algae. Recent reports of tetrameric PSI have raised questions regarding its structural basis, physiological role, phylogenetic distribution and evolutionary significance. Here, we examined PSI in 61 cyanobacteria, showing that tetrameric PSI, which correlates with the psaL gene and a distinct genomic structure, is widespread among heterocyst-forming cyanobacteria and their close relatives. Physiological studies revealed that expression of tetrameric PSI is favoured under high light, with an increased content of novel PSI-bound carotenoids (myxoxanthophyll, canthaxanthan and echinenone). In sum, this work suggests that tetrameric PSI is an adaptation to high light intensity, and that change in PsaL leads to monomerization of trimeric PSI, supporting the hypothesis of tetrameric PSI being the evolutionary intermediate in the transition from cyanobacterial trimeric PSI to monomeric PSI in plants and algae.

Original languageEnglish
Pages (from-to)1309-1319
Number of pages11
JournalNature Plants
Issue number12
Publication statusPublished - Dec-2019

ID: 109494019