A mitochondrial protein homologous to the mammalian peripheral-type benzodiazepine receptor is essential for stress adaptation in plants.
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.
Frank
Wolfgang
W
Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104 Freiburg, Germany. wolfgang.frank@biologie.uni-freiburg.de
Baar
Kim-Miriam
KM
Qudeimat
Enas
E
Woriedh
Mayada
M
Alawady
Ali
A
Ratnadewi
Diah
D
Gremillon
Louis
L
Grimm
Bernhard
B
Reski
Ralf
R
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
D024101:Mitochondrial Proteins; D010940:Plant Proteins; D011524:Protoporphyrins; D011963:Receptors, GABA-A; D012965:Sodium Chloride; D000040:Abscisic Acid; D006861:Hydrogen Peroxide; C028025:protoporphyrin IX