Primary carbon partitioning in red algae and green plants

• Applicant: Professor Dr. Andreas P.M. Weber
• Subject Area: Plant Biochemistry and Biophysics
• Term: from 2008 to 2013
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 96785681

While the primary path of carbon is remarkably conserved in photosynthetic organisms, significant variation exists in the ways that carbon exits the Calvin cycle, especially when all photosynthetic organisms are considered, not just plants. Most terrestrial eukaryotic photosynthetic organisms belong to the Viridiplantae, which are characterized by (1) chloroplasts that are bounded by two envelope membranes, (2) use of chlorophyll a and b, (3) storage of starch inside the chloroplast stroma, and (4) synthesis of sucrose in the cytosol. In land plants and green algae, the export of the products of the Calvin-Benson cycle, triose phosphates GAP and DAP, from chloroplasts to the cytosol is mediated by a triose phosphate/phosphate antiporter [1]. Paralogous genes encoding this class of transporters can also be found in the genomes of the red algae and in members of the Chromalveolata [2]. However, only members of the Viridiplantae partition photoassimilates between a plastidic starch pool and cytosolic sucrose biosynthesis. We hypothesize that different strategies of carbon partitioning are reflected by the kinetic properties of plastidic phosphate translocators. This hypothesis will be tested by in vitro and in vivo experiments using phosphate translocators from red algae.

• DFG Programme: Research Grants