title: Oxidation-reduction and reactive oxygen species homeostasis in mutant plants with respiratory chain complex I dysfunction.
abstract: Mutations in a mitochondrial or nuclear gene encoding respiratory chain complex I subunits lead to decreased or a total absence of complex I activity. Plant mutants with altered or lost complex I activity adapt their respiratory metabolism by inducing alternative pathways of the respiratory chain and changing energy metabolism. Apparently, complex I is a crucial component of the oxidation-reduction (redox) regulatory system in photosynthetic cells, and alternative NAD(P)H dehydrogenases of the mitochondrial electron transport chain (mtETC) cannot fully compensate for its impairment. In most cases, dysfunction of complex I is associated with lowered or unchanged hydrogen peroxide (H(2)O(2)) concentrations, but increased superoxide (O(2)(-)) levels. Higher production of reactive oxygen species (ROS) by mitochondria in the mosaic (MSC16) cucumber mutant may be related to retrograde signalling. Different effects of complex I dysfunction on H(2)O(2) and O(2)(-) levels in described mutants might result from diverse regulation of processes involved in H(2)O(2) and O(2)(-) production. Often, dysfunction of complex I did not lead to oxidative stress, but increased the capacity of the antioxidative system and enhanced stress tolerance. The new cellular homeostasis in mutants with dysfunction of complex I allows growth and development, reflecting the plasticity of plant metabolism.
authors.affiliation: Department of Plant Bioenergetics, Institute of Experimental Plant Biology and Biotechnology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.
authors.forename: Izabela M
authors.initials: IM
authors.lastname: Juszczuk
authors.forename: Bożena
authors.initials: B
authors.lastname: Szal
authors.forename: Anna M
authors.initials: AM
authors.lastname: Rychter
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D018553:Cucumis sativus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D042967:Electron Transport Complex I / Q000235:genetics / Q000378:metabolism*; D006706:Homeostasis; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D009252:NADPH Dehydrogenase / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism; D063245:Plant Development; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D010944:Plants / Q000235:genetics* / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction; D000099188:Alternative Oxidase
chemical_list: D000975:Antioxidants; D042967:Electron Transport Complex I; D024101:Mitochondrial Proteins; D009252:NADPH Dehydrogenase; D010088:Oxidoreductases; D010940:Plant Proteins; D017382:Reactive Oxygen Species; D000099188:Alternative Oxidase