A plastid terminal oxidase comes to light: implications for carotenoid biosynthesis and chlororespiration.
Inactivation of a plastid located quinone-oxygen oxidoreductase gene in the immutans Arabidopsis mutant leads to a photobleached phenotype because of a lack of photoprotective carotenoids. Inactivation of the corresponding gene in the ghost tomato mutant leads to a similar phenotype in leaves and to carotenoid deficiency in petals and ripe fruits. This plastid terminal oxidase (the first to be cloned and biochemically characterized) resembles the mitochondrial cyanide-insensitive alternative oxidase. Here, we propose a model integrating this novel oxidase as a component of an electron transport chain associated to carotenoid desaturation, as well as to a respiratory activity within plastids.
Carol
P
P
Laboratoire de Génétique Moléculaire des Plantes, UMR5575, CNRS, Université Joseph Fourier, BP53X, Grenoble 9, Cedex, France.
Kuntz
M
M
D017360:Arabidopsis / Q000201:enzymology; D002338:Carotenoids / Q000096:biosynthesis*; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D018087:Plastids / Q000201:enzymology*
D002338:Carotenoids; D010088:Oxidoreductases; D010100:Oxygen