Elevated growth temperature can enhance photosystem I trimer formation and affects xanthophyll biosynthesis in cyanobacterium synechocystis sp. PCC6803 Cells

Kinga Kłodawska, László Kovács, Zsuzsanna Várkonyi, Mihály Kis, Özge Sozer, Hajnalka Laczkó-Dobos, Ottilia Kóbori, Ildikó Domonkos, Kazimierz Strzałka, Zoltán Gombos, Przemysław Malec

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

In the thylakoid membranes of the mesophilic cyanobacterium Synechocystis PCC6803, PSI reaction centers (RCs) are organized as monomers and trimers. PsaL, a 16 kDa hydrophobic protein, a subunit of the PSI RC, was previously identified as crucial for the formation of PSI trimers. In this work, the physiological effects accompanied by PSI oligomerization were studied using a PsaL-deficient mutant (ΔpsaL), not able to form PSI trimers, grown at various temperatures. We demonstrate that in wild-type Synechocystis, the monomer to trimer ratio depends on the growth temperature. The inactivation of the psaL gene in Synechocystis grown phototropically at 30 °C induces profound morphological changes, including the accumulation of glycogen granules localized in the cytoplasm, resulting in the separation of particular thylakoid layers. The carotenoid composition in ΔpsaL shows that PSI monomerization leads to an increased accumulation of myxoxantophyll, zeaxanthin and echinenone irrespective of the temperature conditions. These xanthophylls are formed at the expense of b-carotene. The measured H2O!CO2 oxygen evolution rates in the ΔpsaL mutant are higher than those observed in the wild type, irrespective of the growth temperature. Moreover, circular dichroism spectroscopy in the visible range reveals that a peak attributable to long-wavelength-absorbing carotenoids is apparently enhanced in the trimer-accumulating wild-type cells. These results suggest that specific carotenoids are accompanied by the accumulation of PSI oligomers and play a role in the formation of PSI oligomer structure.

Original languageEnglish
Pages (from-to)558-571
Number of pages14
JournalPlant and Cell Physiology
Volume56
Issue number3
DOIs
Publication statusPublished - Jan 1 2015

Keywords

  • CD spectra
  • Carotenoids
  • PSI trimer
  • Psaldeficient mutant
  • Synechocystis

ASJC Scopus subject areas

  • Physiology
  • Plant Science
  • Cell Biology

Fingerprint Dive into the research topics of 'Elevated growth temperature can enhance photosystem I trimer formation and affects xanthophyll biosynthesis in cyanobacterium synechocystis sp. PCC6803 Cells'. Together they form a unique fingerprint.

  • Cite this