Effects of Acetate on Facultative Autotrophy in<i>Chlamydomonas reinhardtii</i> Assessed by Photosynthetic Measurements and Stable Isotope Analyses

DOI PDF 被引用文献5件
  • Peter B. Heifetz
    Developmental Cellular and Molecular Biology Group (P.B.H., B.F., J.E.B.) and
  • Britta Förster
    Developmental Cellular and Molecular Biology Group (P.B.H., B.F., J.E.B.) and
  • C. Barry Osmond
    Research School of Biological Sciences, Institute of Advanced Studies, The Australian National University, Box 3252, Weston Creek, Australian Capital Territory 2611, Australia (C.B.O.)
  • Lawrence J. Giles
    Department of Botany (L.J.G.), Duke University, Durham, North Carolina 27708–1000; and
  • John E. Boynton
    Developmental Cellular and Molecular Biology Group (P.B.H., B.F., J.E.B.) and

抄録

<jats:title>Abstract</jats:title> <jats:p>The green alga Chlamydomonas reinhardtii can grow photoautotrophically utilizing CO2, heterotrophically utilizing acetate, and mixotrophically utilizing both carbon sources. Growth of cells in increasing concentrations of acetate plus 5% CO2 in liquid culture progressively reduced photosynthetic CO2 fixation and net O2 evolution without effects on respiration, photosystem II efficiency (as measured by chlorophyll fluorescence), or growth. Using the technique of on-line oxygen isotope ratio mass spectrometry, we found that mixotrophic growth in acetate is not associated with activation of the cyanide-insensitive alternative oxidase pathway. The fraction of carbon biomass resulting from photosynthesis, determined by stable carbon isotope ratio mass spectrometry, declined dramatically (about 50%) in cells grown in acetate with saturating light and CO2. Under these conditions, photosynthetic CO2 fixation and O2 evolution were also reduced by about 50%. Some growth conditions (e.g. limiting light, high acetate, solid medium in air) virtually abolished photosynthetic carbon gain. These effects of acetate were exacerbated in mutants with slowed electron transfer through the D1 reaction center protein of photosystem II or impaired chloroplast protein synthesis. Therefore, in mixotrophically grown cells of C. reinhardtii, interpretations of the effects of environmental or genetic manipulations of photosynthesis are likely to be confounded by acetate in the medium.</jats:p>

収録刊行物

  • Plant Physiology

    Plant Physiology 122 (4), 1439-1446, 2000-04-01

    Oxford University Press (OUP)

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