title: Different molecular bases underlie the mitochondrial respiratory activity in the homoeothermic spadices of Symplocarpus renifolius and the transiently thermogenic appendices of Arum maculatum.
abstract: Symplocarpus renifolius and Arum maculatum are known to produce significant heat during the course of their floral development, but they use different regulatory mechanisms, i.e. homoeothermic compared with transient thermogenesis. To further clarify the molecular basis of species-specific thermogenesis in plants, in the present study we have analysed the native structures and expression patterns of the mitochondrial respiratory components in S. renifolius and A. maculatum. Our comparative analysis using Blue native PAGE combined with nano LC (liquid chromatography)-MS/MS (tandem MS) has revealed that the constituents of the respiratory complexes in both plants were basically similar, but that several mitochondrial components appeared to be differently expressed in their thermogenic organs. Namely, complex II in S. renifolius was detected as a 340 kDa product, suggesting an oligomeric or supramolecular structure in vivo. Moreover, the expression of an external NAD(P)H dehydrogenase was found to be higher in A. maculatum than in S. renifolius, whereas an internal NAD(P)H dehydrogenase was expressed at a similar level in both species. Alternative oxidase was detected as smear-like signals that were elongated on the first dimension with a peak at around 200 kDa in both species. The significance and implication of these data are discussed in terms of thermoregulation in plants.
authors.affiliation: The United Graduate School of Agricultural Sciences, Iwate University, 3-18-8 Ueda, Morioka, Iwate, 020-8550, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kakizaki
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Moore
authors.forename: Kikukatsu
authors.initials: K
authors.lastname: Ito
mesh_terms: D000595:Amino Acid Sequence; D029064:Araceae / Q000235:genetics / Q000378:metabolism*; D031058:Arum / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D004579:Electron Transport; D015180:Electrophoresis, Gel, Two-Dimensional; D035264:Flowers; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009252:NADPH Dehydrogenase / Q000235:genetics / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D053719:Tandem Mass Spectrometry; D022722:Thermogenesis; D000099188:Alternative Oxidase
chemical_list: D024101:Mitochondrial Proteins; D009252:NADPH Dehydrogenase; D010088:Oxidoreductases; D010940:Plant Proteins; D000099188:Alternative Oxidase