title: Light regulation of mitochondrial alternative oxidase pathway during greening of etiolated wheat seedlings.
abstract: This study deals with effects of de-etiolation (48h) of spring wheat (Triticum aestivum L., var. Irgina) seedlings on differential expression of AOX1 genes, levels of AOX protein and the alternative respiratory pathway (AP) capacity. As a result of exposure to continuous irradiation of dark-grown wheat seedlings, the respiratory activity and AP capacity in leaves significantly increased during the first 6h of studies. Expression of AOX1a was up-regulated by light and proved consistent with changes in the AP capacity. Effects on expression of AOX1c were less pronounced. Immunoblot analysis showed three distinct bands of AOX with molecular weights of 34, 36 and 38kDa, with no significant changes in the relative levels during de-etiolation. The lack of a clear correlation between AOX protein amount, AOX1a expression, and AP capacity suggests post-translational control of the enzyme activation. The AOX1a suppression and a decrease in the AP capacity correlated with the sugar pool depletion after 24h of the de-etiolation, which may mean a possible substrate dependence of the AOX activity in the green cells. More efficient malate oxidation by mitochondria as well as the higher AOX capacity during the first 6h of de-etiolation was detected, whereas respiration and AOX capacity with exogenous NADH and glycine increased after 6 and 24h, respectively. We conclude that AOX plays an important role during development of an actively photosynthesizing cell, and can rapidly adapt to changes in metabolism and photosynthesis.
authors.affiliation: Institute of Biology, Komi Science Centre, Ural Branch, Russian Academy of Sciences, 28 Kommunisticheskaya Str., 167982 Syktyvkar, Russia. Electronic address: garmash@ib.komisc.ru.
authors.forename: Elena V
authors.initials: EV
authors.lastname: Garmash
authors.affiliation: Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences, 132 Lermontov Str., 664033 Irkutsk, Russia.
authors.forename: Olga I
authors.initials: OI
authors.lastname: Grabelnych
authors.affiliation: Institute of Biology, Komi Science Centre, Ural Branch, Russian Academy of Sciences, 28 Kommunisticheskaya Str., 167982 Syktyvkar, Russia.
authors.forename: Iliya O
authors.initials: IO
authors.lastname: Velegzhaninov
authors.affiliation: Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences, 132 Lermontov Str., 664033 Irkutsk, Russia.
authors.forename: Olga A
authors.initials: OA
authors.lastname: Borovik
authors.affiliation: Institute of Biology, Komi Science Centre, Ural Branch, Russian Academy of Sciences, 28 Kommunisticheskaya Str., 167982 Syktyvkar, Russia.
authors.forename: Igor V
authors.initials: IV
authors.lastname: Dalke
authors.affiliation: Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences, 132 Lermontov Str., 664033 Irkutsk, Russia.
authors.forename: Victor K
authors.initials: VK
authors.lastname: Voinikov
authors.affiliation: Institute of Biology, Komi Science Centre, Ural Branch, Russian Academy of Sciences, 28 Kommunisticheskaya Str., 167982 Syktyvkar, Russia.
authors.forename: Tamara K
authors.initials: TK
authors.lastname: Golovko
mesh_terms: D002241:Carbohydrates / Q000032:analysis; D002245:Carbon Dioxide / Q000378:metabolism; D019069:Cell Respiration / Q000528:radiation effects; D003576:Electron Transport Complex IV / Q000378:metabolism; D064527:Etiolation / Q000528:radiation effects*; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D017343:Genes, Plant; D015151:Immunoblotting; D007527:Isoenzymes / Q000378:metabolism; D008027:Light; D008928:Mitochondria / Q000378:metabolism* / Q000528:radiation effects; D024101:Mitochondrial Proteins / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D010788:Photosynthesis / Q000528:radiation effects; D018515:Plant Leaves / Q000502:physiology / Q000528:radiation effects; D010940:Plant Proteins / Q000378:metabolism*; D036226:Seedlings / Q000502:physiology* / Q000528:radiation effects; D015398:Signal Transduction / Q000528:radiation effects; D012995:Solubility; D014908:Triticum / Q000201:enzymology* / Q000235:genetics / Q000502:physiology / Q000528:radiation effects*; D000099188:Alternative Oxidase
chemical_list: D002241:Carbohydrates; D002245:Carbon Dioxide; D003576:Electron Transport Complex IV; D007527:Isoenzymes; D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010100:Oxygen; D010940:Plant Proteins; D000099188:Alternative Oxidase
keywords: Alternative oxidase; De-etiolation; Gene expression; Respiration; Triticum aestivum