Effects of low CO2 on NAD(P)H dehydrogenase, a mediator of cyclic electron transport around photosystem I in the cyanobacterium synechocystis PCC6803

Plant Cell Physiol. 2003 May;44(5):534-40. doi: 10.1093/pcp/pcg067.


The expression and activity of type-1 NAD(P)H dehydrogenase (NDH-1) was compared between cells of Synechocystis PCC6803 grown in high (H-cells) and low (L-cells) CO(2) conditions. Western analysis indicated that L-cells contain higher amounts of the NDH-1 subunits, NdhH, NdhI and NdhK. An NADPH-specific subcomplex of NDH-1 showed higher NADPH-nitroblue tetrazolium oxidoreductase activity in L-cells. The activities of both NADPH-menadione oxidoreductase and light-dependent NADPH oxidation driven by photosystem I were much higher in L-cells than in H-cells. The initial rate of re-reduction of P700(+) following actinic light illumination in the presence of DCMU under background far-red light was enhanced in L-cells. In addition, rotenone, a specific inhibitor of NDH-1, suppressed the relative rate of post-illumination increase in Chl fluorescence of L-cells more than that of H-cells, suggesting that the involvement of NDH-1 in cyclic electron flow around photosystem I was enhanced by low CO(2). Taken together, these results suggest that NDH-1 complex and NDH-1-mediated cyclic electron transport are stimulated by low CO(2) and function in the acclimation of cyanobacteria to low CO(2).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • Carbon Dioxide / pharmacology*
  • Chlorophyll / metabolism
  • Cyanobacteria / drug effects*
  • Cyanobacteria / enzymology
  • Cyanobacteria / metabolism
  • Diuron / pharmacology
  • Electron Transport / drug effects
  • Light
  • NADPH Dehydrogenase / metabolism*
  • Photosynthetic Reaction Center Complex Proteins / drug effects*
  • Photosynthetic Reaction Center Complex Proteins / metabolism
  • Photosynthetic Reaction Center Complex Proteins / radiation effects


  • Photosynthetic Reaction Center Complex Proteins
  • Chlorophyll
  • Carbon Dioxide
  • Diuron
  • NADPH Dehydrogenase