title: Plastid Terminal Oxidase as a Route to Improving Plant Stress Tolerance: Known Knowns and Known Unknowns.
abstract: A plastid-localized terminal oxidase, PTox, was first described due to its role in chloroplast development, with plants lacking PTox producing white sectors on their leaves. This phenotype is explained as being due to PTox playing a role in carotenoid biosynthesis, as a cofactor of phytoene desaturase. Co-occurrence of PTox with a chloroplast-localized NADPH dehydrogenase (NDH) has suggested the possibility of a functional respiratory pathway in plastids. Evidence has also been found that, in certain stress-tolerant plant species, PTox can act as an electron acceptor from PSII, making it a candidate for engineering stress-tolerant crops. However, attempts to induce such a pathway via overexpression of the PTox protein have failed to date. Here we review the current understanding of PTox function in higher plants and discuss possible barriers to inducing PTox activity to improve stress tolerance.
authors.affiliation: Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK giles.johnson@manchester.ac.uk.
authors.forename: Giles N
authors.initials: GN
authors.lastname: Johnson
authors.affiliation: Department of Plant Nutrition, Wroclaw University of Environmental and Life Sciences, ul. Grunwaldzka 53, 50-357 Wroclaw, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Stepien
mesh_terms: D000222:Adaptation, Physiological; D004579:Electron Transport; D010088:Oxidoreductases / Q000737:chemistry / Q000378:metabolism*; D018521:Plant Physiological Phenomena; D018087:Plastids / Q000201:enzymology*; D013312:Stress, Physiological
chemical_list: D010088:Oxidoreductases
keywords: Photosynthesis; Plastid terminal oxidase; alternative oxidase; electron transport; oxidative stress