title: The Arabidopsis thaliana aquaporin AtPIP1;2 is a physiologically relevant CO₂ transport facilitator.
abstract: Cellular exchange of carbon dioxide (CO₂) is of extraordinary importance for life. Despite this significance, its molecular mechanisms are still unclear and a matter of controversy. In contrast to other living organisms, plants are physiologically limited by the availability of CO₂. In most plants, net photosynthesis is directly dependent on CO₂ diffusion from the atmosphere to the chloroplast. Thus, it is important to analyze CO₂ transport with regards to its effect on photosynthesis. A mutation of the Arabidopsis thaliana AtPIP1;2 gene, which was characterized as a non-water transporting but CO₂ transport-facilitating aquaporin in heterologous expression systems, correlated with a reduction in photosynthesis under a wide range of atmospheric CO₂ concentrations. Here, we could demonstrate that the effect was caused by reduced CO₂ conductivity in leaf tissue. It is concluded that the AtPIP1;2 gene product limits CO₂ diffusion and photosynthesis in leaves.
authors.affiliation: Darmstadt University of Technology, Applied Plant Science, Schnittspahnstr. 10, D-64287 Darmstadt, Germany.
authors.forename: Marlies
authors.initials: M
authors.lastname: Heckwolf
authors.forename: Dianne
authors.initials: D
authors.lastname: Pater
authors.forename: David T
authors.initials: DT
authors.lastname: Hanson
authors.forename: Ralf
authors.initials: R
authors.lastname: Kaldenhoff
mesh_terms: D020346:Aquaporins / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001272:Atmosphere; D001483:Base Sequence; D001692:Biological Transport; D002245:Carbon Dioxide / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism; D004058:Diffusion; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010539:Permeability; D010788:Photosynthesis / Q000502:physiology*; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D018526:Plant Transpiration; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D008565:Membrane Proteins
chemical_list: D020346:Aquaporins; D029681:Arabidopsis Proteins; D002245:Carbon Dioxide; D002734:Chlorophyll; D012273:Ribulose-Bisphosphate Carboxylase; C085550:At2g45960 protein, Arabidopsis; D008565:Membrane Proteins