CO2 CONCENTRATING MECHANISMS IN ALGAE: Mechanisms, Environmental Modulation, and Evolution (original) (raw)

2005, Annual Review of Plant Biology

The evolution of organisms capable of oxygenic photosynthesis paralleled a long-term reduction in atmospheric CO 2 and the increase in O 2 . Consequently, the competition between O 2 and CO 2 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 CO 2 concentrations (CO 2 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. 99 Annu. Rev. Plant. Biol. 2005.56:99-131. Downloaded from arjournals.annualreviews.org by UNIVERSITY OF NEW MEXICO on 06/02/05. For personal use only.