title: A mitochondrial protein homologous to the mammalian peripheral-type benzodiazepine receptor is essential for stress adaptation in plants.
abstract: The cloning of abiotic stress-inducible genes from the moss Physcomitrella patens led to the identification of the gene PpTSPO1, encoding a protein homologous to the mammalian mitochondrial peripheral-type benzodiazepine receptor and the bacterial tryptophane-rich sensory protein. This class of proteins is involved in the transport of intermediates of the tetrapyrrole biosynthesis pathway. Like the mammalian homologue, the PpTSPO1 protein is localized to mitochondria. The generation of PpTSPO1-targeted moss knock-out lines revealed an essential function of the gene in abiotic stress adaptation. Under stress conditions, the PpTSPO1 null mutants show elevated H(2)O(2) levels, enhanced lipid peroxidation and cell death, indicating an important role of PpTSPO1 in redox homeostasis. We hypothesize that PpTSPO1 acts to direct porphyrin precursors to the mitochondria for heme formation, and is involved in the removal of photoreactive tetrapyrrole intermediates.
authors.affiliation: Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104 Freiburg, Germany. wolfgang.frank@biologie.uni-freiburg.de
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Frank
authors.forename: Kim-Miriam
authors.initials: KM
authors.lastname: Baar
authors.forename: Enas
authors.initials: E
authors.lastname: Qudeimat
authors.forename: Mayada
authors.initials: M
authors.lastname: Woriedh
authors.forename: Ali
authors.initials: A
authors.lastname: Alawady
authors.forename: Diah
authors.initials: D
authors.lastname: Ratnadewi
authors.forename: Louis
authors.initials: L
authors.lastname: Gremillon
authors.forename: Bernhard
authors.initials: B
authors.lastname: Grimm
authors.forename: Ralf
authors.initials: R
authors.lastname: Reski
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000220:Adaptation, Biological / Q000235:genetics*; D019068:Bryopsida / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D006861:Hydrogen Peroxide / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D009154:Mutation; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D011524:Protoporphyrins / Q000378:metabolism; D011963:Receptors, GABA-A / Q000737:chemistry; D020539:Sequence Analysis, Protein; D012965:Sodium Chloride / Q000494:pharmacology
chemical_list: D024101:Mitochondrial Proteins; D010940:Plant Proteins; D011524:Protoporphyrins; D011963:Receptors, GABA-A; D012965:Sodium Chloride; D000040:Abscisic Acid; D006861:Hydrogen Peroxide; C028025:protoporphyrin IX