title: The gene expression landscape of thermogenic skunk cabbage suggests critical roles for mitochondrial and vacuolar metabolic pathways in the regulation of thermogenesis.
abstract: Floral thermogenesis has been described in several plant species. Because of the lack of comprehensive gene expression profiles in thermogenic plants, the molecular mechanisms by which floral thermogenesis is regulated remain to be established. We examined the gene expression landscape of skunk cabbage (Symplocarpus renifolius) during thermogenic and post-thermogenic stages and identified expressed sequence tags from different developmental stages of the inflorescences using super serial analysis of gene expression (SuperSAGE). In-depth analysis suggested that cellular respiration and mitochondrial functions are significantly enhanced during the thermogenic stage. In contrast, genes involved in stress responses and protein degradation were significantly up-regulated during post-thermogenic stages. Quantitative comparisons indicated that the expression levels of genes involved in cellular respiration were higher in thermogenic spadices than in Arabidopsis inflorescences. Thermogenesis-associated genes seemed to be expressed abundantly in the peripheral tissues of the spadix. Our results suggest that cellular respiration and mitochondrial metabolism play key roles in heat production during floral thermogenesis. On the other hand, vacuolar cysteine protease and other degradative enzymes seem to accelerate senescence and terminate thermogenesis in the post-thermogenic stage.
authors.affiliation: Interdisciplinary Research Organization, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-nishi, Miyazaki, Japan. ykoina@cc.miyazaki-u.ac.jp
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Ito-Inaba
authors.forename: Yamato
authors.initials: Y
authors.lastname: Hida
authors.forename: Hideo
authors.initials: H
authors.lastname: Matsumura
authors.forename: Hiromi
authors.initials: H
authors.lastname: Masuko
authors.forename: Fumiko
authors.initials: F
authors.lastname: Yazu
authors.forename: Ryohei
authors.initials: R
authors.lastname: Terauchi
authors.forename: Masao
authors.initials: M
authors.lastname: Watanabe
authors.forename: Takehito
authors.initials: T
authors.lastname: Inaba
mesh_terms: D029064:Araceae / Q000235:genetics* / Q000502:physiology; D019069:Cell Respiration; D016000:Cluster Analysis; D020224:Expressed Sequence Tags; D035264:Flowers / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D008928:Mitochondria / Q000378:metabolism*; D018749:RNA, Plant / Q000235:genetics; D013696:Temperature; D059467:Transcriptome; D014617:Vacuoles / Q000378:metabolism*
chemical_list: D018749:RNA, Plant