title: Distinct Cellular Locations of Carbonic Anhydrases Mediate Carbon Dioxide Control of Stomatal Movements.
abstract: Elevated carbon dioxide (CO2) in leaves closes stomatal apertures. Research has shown key functions of the β-carbonic anhydrases (βCA1 and βCA4) in rapid CO2-induced stomatal movements by catalytic transmission of the CO2 signal in guard cells. However, the underlying mechanisms remain unclear, because initial studies indicate that these Arabidopsis (Arabidopsis thaliana) βCAs are targeted to distinct intracellular compartments upon expression in tobacco (Nicotiana benthamiana) cells. Which cellular location of these enzymes plays a key role in native guard cells in CO2-regulated stomatal movements remains unknown. Here, we express fluorescently tagged CAs in guard cells of ca1ca4 double-mutant plants and show that the specific locations of βCA4 at the plasma membrane and βCA1 in native guard cell chloroplasts each can mediate rapid CO2 control of stomatal movements. Localization and complementation analyses using a mammalian αCAII-yellow fluorescent protein in guard cells further show that cytoplasmic localization is also sufficient to restore CO2 regulation of stomatal conductance. Mathematical modeling of cellular CO2 catalysis suggests that the dynamics of the intracellular HCO3 (-) concentration change in guard cells can be driven by plasma membrane and cytoplasmic localizations of CAs but not as clearly by chloroplast targeting. Moreover, modeling supports the notion that the intracellular HCO3 (-) concentration dynamics in guard cells are a key mechanism in mediating CO2-regulated stomatal movements but that an additional chloroplast role of CAs exists that has yet to be identified.
authors.affiliation: College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China (H.H., L.Y., C.X.);Division of Biological Sciences, Cell and Developmental Biology Section (H.H., A.R., M.B., C.B.E., J.I.S.) andPhysics Department (W.-J.R.), University of California, San Diego, La Jolla, California 92093-0116; andDepartment of Physiology and Biophysics (R.O., W.F.B.) andDepartment of Medicine (W.F.B.), Case Western Reserve University School of Medicine, Cleveland, Ohio 44106 huhh@mail.hzau.edu.cn jischroeder@ucsd.edu.
authors.forename: Honghong
authors.identifier: http://orcid.org/0000-0003-0538-6646
authors.initials: H
authors.lastname: Hu
authors.affiliation: College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China (H.H., L.Y., C.X.);Division of Biological Sciences, Cell and Developmental Biology Section (H.H., A.R., M.B., C.B.E., J.I.S.) andPhysics Department (W.-J.R.), University of California, San Diego, La Jolla, California 92093-0116; andDepartment of Physiology and Biophysics (R.O., W.F.B.) andDepartment of Medicine (W.F.B.), Case Western Reserve University School of Medicine, Cleveland, Ohio 44106.
authors.forename: Wouter-Jan
authors.initials: WJ
authors.lastname: Rappel
authors.affiliation: College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China (H.H., L.Y., C.X.);Division of Biological Sciences, Cell and Developmental Biology Section (H.H., A.R., M.B., C.B.E., J.I.S.) andPhysics Department (W.-J.R.), University of California, San Diego, La Jolla, California 92093-0116; andDepartment of Physiology and Biophysics (R.O., W.F.B.) andDepartment of Medicine (W.F.B.), Case Western Reserve University School of Medicine, Cleveland, Ohio 44106.
authors.forename: Rossana
authors.initials: R
authors.lastname: Occhipinti
authors.affiliation: College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China (H.H., L.Y., C.X.);Division of Biological Sciences, Cell and Developmental Biology Section (H.H., A.R., M.B., C.B.E., J.I.S.) andPhysics Department (W.-J.R.), University of California, San Diego, La Jolla, California 92093-0116; andDepartment of Physiology and Biophysics (R.O., W.F.B.) andDepartment of Medicine (W.F.B.), Case Western Reserve University School of Medicine, Cleveland, Ohio 44106.
authors.forename: Amber
authors.initials: A
authors.lastname: Ries
authors.affiliation: College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China (H.H., L.Y., C.X.);Division of Biological Sciences, Cell and Developmental Biology Section (H.H., A.R., M.B., C.B.E., J.I.S.) andPhysics Department (W.-J.R.), University of California, San Diego, La Jolla, California 92093-0116; andDepartment of Physiology and Biophysics (R.O., W.F.B.) andDepartment of Medicine (W.F.B.), Case Western Reserve University School of Medicine, Cleveland, Ohio 44106.
authors.forename: Maik
authors.identifier: http://orcid.org/0000-0001-6675-273X
authors.initials: M
authors.lastname: Böhmer
authors.affiliation: College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China (H.H., L.Y., C.X.);Division of Biological Sciences, Cell and Developmental Biology Section (H.H., A.R., M.B., C.B.E., J.I.S.) andPhysics Department (W.-J.R.), University of California, San Diego, La Jolla, California 92093-0116; andDepartment of Physiology and Biophysics (R.O., W.F.B.) andDepartment of Medicine (W.F.B.), Case Western Reserve University School of Medicine, Cleveland, Ohio 44106.
authors.forename: Lei
authors.initials: L
authors.lastname: You
authors.affiliation: College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China (H.H., L.Y., C.X.);Division of Biological Sciences, Cell and Developmental Biology Section (H.H., A.R., M.B., C.B.E., J.I.S.) andPhysics Department (W.-J.R.), University of California, San Diego, La Jolla, California 92093-0116; andDepartment of Physiology and Biophysics (R.O., W.F.B.) andDepartment of Medicine (W.F.B.), Case Western Reserve University School of Medicine, Cleveland, Ohio 44106.
authors.forename: Chuanlei
authors.initials: C
authors.lastname: Xiao
authors.affiliation: College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China (H.H., L.Y., C.X.);Division of Biological Sciences, Cell and Developmental Biology Section (H.H., A.R., M.B., C.B.E., J.I.S.) andPhysics Department (W.-J.R.), University of California, San Diego, La Jolla, California 92093-0116; andDepartment of Physiology and Biophysics (R.O., W.F.B.) andDepartment of Medicine (W.F.B.), Case Western Reserve University School of Medicine, Cleveland, Ohio 44106.
authors.forename: Cawas B
authors.initials: CB
authors.lastname: Engineer
authors.affiliation: College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China (H.H., L.Y., C.X.);Division of Biological Sciences, Cell and Developmental Biology Section (H.H., A.R., M.B., C.B.E., J.I.S.) andPhysics Department (W.-J.R.), University of California, San Diego, La Jolla, California 92093-0116; andDepartment of Physiology and Biophysics (R.O., W.F.B.) andDepartment of Medicine (W.F.B.), Case Western Reserve University School of Medicine, Cleveland, Ohio 44106.
authors.forename: Walter F
authors.initials: WF
authors.lastname: Boron
authors.affiliation: College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China (H.H., L.Y., C.X.);Division of Biological Sciences, Cell and Developmental Biology Section (H.H., A.R., M.B., C.B.E., J.I.S.) andPhysics Department (W.-J.R.), University of California, San Diego, La Jolla, California 92093-0116; andDepartment of Physiology and Biophysics (R.O., W.F.B.) andDepartment of Medicine (W.F.B.), Case Western Reserve University School of Medicine, Cleveland, Ohio 44106 huhh@mail.hzau.edu.cn jischroeder@ucsd.edu.
authors.forename: Julian I
authors.initials: JI
authors.lastname: Schroeder
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism*; D002256:Carbonic Anhydrases / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002736:Chloroplasts / Q000235:genetics / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D059828:Plant Cells / Q000378:metabolism; D054046:Plant Stomata / Q000378:metabolism / Q000502:physiology*; D030821:Plants, Genetically Modified; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D008164:Luminescent Proteins; C054562:yellow fluorescent protein, Bacteria; D002245:Carbon Dioxide; D049452:Green Fluorescent Proteins; C000609123:CA1 protein, Arabidopsis; C000609124:CA4 protein, Arabidopsis; D002256:Carbonic Anhydrases