Abstract
When grown photoautotrophically at air levels of CO2, Chlamydomonas reinhardii possesses a system involving active transport of inorganic carbon which increases the intracellular CO2 concentration considerably above ambient, thereby stimulating photosynthetic CO2 assimilation. In previous investigations, two mutant strains of this unicellular green alga deficient in some component of this CO2-concentrating system were recovered as strains requiring high levels of CO2 to support photoautotrophic growth. One of the mutants, ca-1-12-1C, is a leaky (nonstringent) CO2-requiring strain deficient in carbonic anhydrase (EC 4.2.1.1) activity, while the other, pmp-1-16-5K, is a stringent CO2-requiring strain deficient in inorganic carbon transport. In the present study a double mutant (ca pmp) was constructed to investigate the physiological and biochemical interaction of the two mutations. The two mutations are unlinked and inherited in a Mendelian fashion. The double mutant was found to have a leaky CO2-requiring phenotype, indicating that the mutation ca-1 overcomes the stringent CO2-requirement conferred by the mutation pmp-1. Several physiological characteristics of the double mutant were very similar to the carbonic-anhydrase-deficient mutant, including high CO2 compensation concentration, photosynthetic CO2 response curve, and deficiency of carbonic-anhydrase activity. However, the labeling pattern of metabolites during photosynthesis in 14CO2 was more like that of the bicarbonatetransport-deficient mutant, and accumulation of internal inorganic carbon was intermediate between that of the two original mutants. These data indicate a previously unsuspected complexity in the Chlamydomonas CO2-concentrating system.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Badger, M.R., Kaplan, A., Berry, J.A. (1980) Internal inorganic carbon pool of Chlamydomonas reinhardtii Evidence for a carbon dioxide-concentrating mechanism. Plant Physiol. 66, 407–413
Beardall, J., Raven, J. (1981) Transport of inorganic carbon and the “CO2 concentrating mechanism” in Chlorella emersonii (Chlorophyceae). J. Phycol. 17, 134–141
Findenegg, G.R. (1976) Correlations between accessibility of carbonic anhydrase for external substrate and regulation of photosynthetic use of CO2 and HCO -3 by Scenedesmus obliquus. Z. Pflanzenphysiol. 79, 428–437
Kaplan, A., Zenvirth, D., Reinhold, L., Berry, J. (1982) Involvement of a primary electrogenic pump in the mechanism for HCO -3 uptake by the Cyanobacterium Anabaena variabilis. Plant Physiol. 69, 978–982
Laing, W.A., Ogren, W.L., Hageman, R.H. (1974) Regulation of soybean net photosynthetic CO2 fixation by the interaction of CO2, O2, and ribulose 1,5-diphosphate carboxylase. Plant Physiol. 54, 678–685
Spalding, M.H., Orgen, W.L. (1982) Photosynthesis is required for induction of the CO2-concentrating system in Chlamydomonas. FEBS Lett. 145, 41–44
Spalding, M.H., Ogren, W.L. (1983) Evidence for a saturable transport component in the inorganic carbon uptake of Chlamydomonas reinhardii. FEBS Lett. 154, 335–338
Spalding, M.H., Spreitzer, R.J., Orgen, W.L. (1983a) Carbonic anhydrase deficient mutant of Chlamydomonas requires elevated carbon dioxide concentration for photoautotrophic growth. Plant Physiol. (in press)
Spalding, M.H., Spreitzer, R.J., Ogren, W.L. (1983b) Reduced inorganic carbon transport in a CO2-requiring mutant of Chlamydomonas reinhardii. Plant Physiol. (in press)
Spreitzer, R.J., Mets, L. (1981) Photosynthesis-deficient mutants of Chlamydomonas reinhardii with associated light-sensitive phenotypes. Plant Physiol. 67, 565–569
Spreitzer, R.J., Orgren, W.L. (1983) Nuclear suppressors of the photosensitivity associated with defective photosynthesis in Chlamydomonas reinhardii. Plant Physiol. 71, 35–39
Wintermans, J.F.G.M., De Mots, A. (1965) Spectrophotometric characteristics of chlorophyll and their phenophytins in ethanol. Biochim. Biophys. Acta 109, 448–453
Zenvirth, D., Kaplan, A. (1981) Uptake and efflux of inorganic carbon in Dunaliella salina. Planta 152, 8–12
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Spalding, M.H., Spreitzer, R.J. & Ogren, W.L. Genetic and physiological analysis of the CO2-concentrating system of Chlamydomonas reinhardii . Planta 159, 261–266 (1983). https://doi.org/10.1007/BF00397534
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00397534