Distinct responses of the mitochondrial respiratory chain to long- and short-term high-light environments in Arabidopsis thaliana.
In order to ensure the cooperative function with the photosynthetic system, the mitochondrial respiratory chain needs to flexibly acclimate to a fluctuating light environment. The non-phosphorylating alternative oxidase (AOX) is a notable respiratory component that may support a cellular redox homeostasis under high-light (HL) conditions. Here we report the distinct acclimatory manner of the respiratory chain to long- and short-term HL conditions and the crucial function of AOX in Arabidopsis thaliana leaves. Plants grown under HL conditions (HL plants) possessed a larger ubiquinone (UQ) pool and a higher amount of cytochrome c oxidase than plants grown under low light conditions (LL plants). These responses in HL plants may be functional for efficient ATP production and sustain the fast plant growth. When LL plants were exposed to short-term HL stress (sHL), the UQ reduction level was transiently elevated. In the wild-type plant, the UQ pool was re-oxidized concomitantly with an up-regulation of AOX. On the other hand, the UQ reduction level of the AOX-deficient aox1a mutant remained high. Furthermore, the plastoquinone pool was also more reduced in the aox1a mutant under such conditions. These results suggest that AOX plays an important role in rapid acclimation of the respiratory chain to sHL, which may support efficient photosynthetic performance.
Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. yoshida.k.ao@m.titech.ac.jp
Keisuke
K
Yoshida
Chihiro K
CK
Watanabe
Takushi
T
Hachiya
Danny
D
Tholen
Masaru
M
Shibata
Ichiro
I
Terashima
Ko
K
Noguchi
D000064:Acclimatization / Q000235:genetics; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D004579:Electron Transport / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D003576:Electron Transport Complex IV / Q000235:genetics / Q000378:metabolism*; D004777:Environment; D015971:Gene Expression Regulation, Enzymologic / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D008027:Light; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D024101:Mitochondrial Proteins; D016254:Mutagenesis, Insertional; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D010788:Photosynthesis / Q000235:genetics; D018515:Plant Leaves / Q000201:enzymology / Q000378:metabolism / Q000528:radiation effects; D010940:Plant Proteins; D013997:Time Factors; D014451:Ubiquinone; D015854:Up-Regulation; D000099188:Alternative Oxidase
D029681:Arabidopsis Proteins; D003576:Electron Transport Complex IV; D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010940:Plant Proteins; D014451:Ubiquinone; D000099188:Alternative Oxidase