title: Ion Channels in Plant Bioenergetic Organelles, Chloroplasts and Mitochondria: From Molecular Identification to Function.
abstract: Recent technical advances in electrophysiological measurements, organelle-targeted fluorescence imaging, and organelle proteomics have pushed the research of ion transport a step forward in the case of the plant bioenergetic organelles, chloroplasts and mitochondria, leading to the molecular identification and functional characterization of several ion transport systems in recent years. Here we focus on channels that mediate relatively high-rate ion and water flux and summarize the current knowledge in this field, focusing on targeting mechanisms, proteomics, electrophysiology, and physiological function. In addition, since chloroplasts evolved from a cyanobacterial ancestor, we give an overview of the information available about cyanobacterial ion channels and discuss the evolutionary origin of chloroplast channels. The recent molecular identification of some of these ion channels allowed their physiological functions to be studied using genetically modified Arabidopsis plants and cyanobacteria. The view is emerging that alteration of chloroplast and mitochondrial ion homeostasis leads to organelle dysfunction, which in turn significantly affects the energy metabolism of the whole organism. Clear-cut identification of genes encoding for channels in these organelles, however, remains a major challenge in this rapidly developing field. Multiple strategies including bioinformatics, cell biology, electrophysiology, use of organelle-targeted ion-sensitive probes, genetics, and identification of signals eliciting specific ion fluxes across organelle membranes should provide a better understanding of the physiological role of organellar channels and their contribution to signaling pathways in plants in the future.
authors.affiliation: Department of Biology, University of Padova, Padova 35121, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Carraretto
authors.affiliation: Department of Biology, University of Padova, Padova 35121, Italy; CNR Institute of Neuroscience, University of Padova, Padova 35121, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Teardo
authors.affiliation: Department of Biology, University of Padova, Padova 35121, Italy.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Checchetto
authors.affiliation: UMR 5168 Laboratoire de Physiologie Cellulaire Végétale (LPCV) CNRS/ UJF / INRA / CEA, Institut de Recherches en Technologies et Sciences pour le Vivant (iRTSV), CEA Grenoble, 38054 Grenoble, France. Electronic address: giovanni.finazzi@cea.fr.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Finazzi
authors.affiliation: Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Aobayama 6-6-07, Sendai 980-8579, Japan. Electronic address: uozumi@biophy.che.tohoku.ac.jp.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Uozumi
authors.affiliation: Department of Biology, University of Padova, Padova 35121, Italy; CNR Institute of Neuroscience, University of Padova, Padova 35121, Italy. Electronic address: ildi@civ.bio.unipd.it.
authors.forename: Ildiko
authors.initials: I
authors.lastname: Szabo
mesh_terms: D002736:Chloroplasts / Q000378:metabolism*; D007473:Ion Channels / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*
chemical_list: D007473:Ion Channels; D010940:Plant Proteins
keywords: chloroplasts; cyanobacteria; endosymbiosis; ion channels; mitochondria; plant physiology