title: CO2 concentrating mechanisms in algae: mechanisms, environmental modulation, and evolution.
abstract: The evolution of organisms capable of oxygenic photosynthesis paralleled a long-term reduction in atmospheric CO2 and the increase in O2. Consequently, the competition between O2 and CO2 for the active sites of RUBISCO became more and more restrictive to the rate of photosynthesis. In coping with this situation, many algae and some higher plants acquired mechanisms that use energy to increase the CO2 concentrations (CO2 concentrating mechanisms, CCMs) in the proximity of RUBISCO. A number of CCM variants are now found among the different groups of algae. Modulating the CCMs may be crucial in the energetic and nutritional budgets of a cell, and a multitude of environmental factors can exert regulatory effects on the expression of the CCM components. We discuss the diversity of CCMs, their evolutionary origins, and the role of the environment in CCM modulation.
authors.affiliation: Department of Marine Sciences, Università Politecnica delle Marche, 60121 Ancona, Italy. m.giordano@univpm.it
authors.forename: Mario
authors.initials: M
authors.lastname: Giordano
authors.forename: John
authors.initials: J
authors.lastname: Beardall
authors.forename: John A
authors.initials: JA
authors.lastname: Raven
mesh_terms: D005075:Biological Evolution; D002245:Carbon Dioxide / Q000378:metabolism*; D002256:Carbonic Anhydrases / Q000378:metabolism; D000458:Cyanobacteria / Q000201:enzymology / Q000378:metabolism; D004777:Environment; D056890:Eukaryota / Q000201:enzymology / Q000378:metabolism*; D010788:Photosynthesis
chemical_list: D002245:Carbon Dioxide; D002256:Carbonic Anhydrases