The effects of salt stress on photosynthetic electron transport and thylakoid membrane proteins in the cyanobacterium Spirulina platensis

Putty Reddy Sudhir, Denys Pogoryelov, László Kovács, Gyõzõ Garab, Sistla D.S. Murthy

Research output: Article

86 Citations (Scopus)

Abstract

The response of Spirulina (Arthrospira) platensis to high salt stress was investigated by incubating the cells in light of moderate intensity in the presence of 0.8 M NaCl. NaCl caused a decrease in photosystem II (PSII) mediated oxygen evolution activity and increase in photosystem I (PSI) activity and the amount of P700. Similarly maximal efficiency of PSII (Fv/Fm) and variable fluorescence (Fv/ Fo) were also declined in salt-stressed cells. Western blot analysis reveal that the inhibition in PSII activity is due to a 40% loss of a thylakoid membrane protein, known as D1, which is located in PSII reaction center. NaCl treatment of cells also resulted in the alterations of other thylakoid membrane proteins: most prominently, a dramatic diminishment of the 47-kDa chlorophyll protein (CP) and 94-kDa protein, and accumulation of a 17-kDa protein band were observed in SDS-PAGE. The changes in 47-kDa and 94-kDa proteins lead to the decreased energy transfer from light harvesting antenna to PSII, which was accompanied by alterations in the chlorophyll fluorescence emission spectra of whole cells and isolated thylakoids. Therefore we conclude that salt stress has various effects on photosynthetic electron transport activities due to the marked alterations in the composition of thylakoid membrane proteins.

Original languageEnglish
Pages (from-to)481-485
Number of pages5
JournalJournal of Biochemistry and Molecular Biology
Volume38
Issue number4
Publication statusPublished - dec. 1 2005

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology

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