What is critical for plant thermogenesis? Differences in mitochondrial activity and protein expression between thermogenic and non-thermogenic skunk cabbages.
Thermogenesis during the blooming of inflorescence is found in several but not all aroids. To understand what is critical for thermogenesis, we investigated the difference between thermogenic and non-thermogenic skunk cabbages (Symplocarpus renifolius and Lysichiton camtschatcensis), which are closely related in morphology and phylogeny. Critical parameters of mitochondrial biogenesis, including density, respiratory activity, and protein expression were compared between these two species. Mitochondrial density, respiratory activity, and the amount of alternative oxidase (AOX) in L. camtschatcensis spadix mitochondria were lower than in S. renifolius spadix mitochondria, while the level of uncoupling protein (UCP) was higher. AOX and UCP mRNAs in L. camtschatcensis were constitutively expressed in various tissues, such as the spadix, the spathe, the stalk, and the leaves. cDNA encoding two putative thermogenic proteins, AOX and UCP were isolated from L. camtschatcensis, and their primary structure was analyzed by multiple alignment and phylogenetic tree reconstruction. AOX and UCP protein of two the skunk cabbage species are closely related in structure, compared with other isoforms in thermogenic plants. Our results suggest that mitochondrial density, respiratory activity, and protein expression, rather than the primary structure of AOX or UCP proteins, may play critical roles in thermogenesis in plants.
Cryobiofrontier Research Center, Iwate University, Morioka, 020-8550, Japan. ykoito@iwate-u.ac.jp
Yasuko
Y
Ito-Inaba
Yamato
Y
Hida
Takehito
T
Inaba
D000595:Amino Acid Sequence; D029064:Araceae / Q000166:cytology / Q000201:enzymology / Q000235:genetics / Q000502:physiology*; D019069:Cell Respiration; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D007473:Ion Channels / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009928:Organ Specificity / Q000235:genetics; D010088:Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013696:Temperature; D000071256:Uncoupling Protein 1; D000099188:Alternative Oxidase
D007473:Ion Channels; D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010940:Plant Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D000071256:Uncoupling Protein 1; D000099188:Alternative Oxidase