Dual function of an <i>Arabidopsis</i> transcription factor DREB2A in water-stress-responsive and heat-stress-responsive gene expression

  • Yoh Sakuma
    *Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan;
  • Kyonoshin Maruyama
    Biological Resources Division, Japan International Research Center for Agricultural Sciences, Tsukuba, Ibaraki 305-8686, Japan;
  • Feng Qin
    Biological Resources Division, Japan International Research Center for Agricultural Sciences, Tsukuba, Ibaraki 305-8686, Japan;
  • Yuriko Osakabe
    *Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan;
  • Kazuo Shinozaki
    RIKEN Plant Science Center, Yokohama, Kanagawa 230-0045, Japan; and
  • Kazuko Yamaguchi-Shinozaki
    *Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan;

説明

<jats:p> Transcription factor DREB2A interacts with a cis-acting dehydration-responsive element (DRE) sequence and activates expression of downstream genes involved in drought- and salt-stress response in <jats:italic>Arabidopsis thaliana</jats:italic> . Intact DREB2A expression does not activate downstream genes under normal growth conditions. A negative regulatory domain exists in the central region of DREB2A, and deletion of this region transforms DREB2A to a constitutive active form ( <jats:italic>DREB2A CA</jats:italic> ). We carried out microarray analysis of transgenic <jats:italic>Arabidopsis</jats:italic> -overexpressing <jats:italic>DREB2A CA</jats:italic> and found that the overexpression of <jats:italic>DREB2A CA</jats:italic> induces not only drought- and salt-responsive genes but also heat-shock (HS)-related genes. Moreover, we found that transient induction of the <jats:italic>DREB2A</jats:italic> occurs rapidly by HS stress, and that the sGFP-DREB2A protein accumulates in nuclei of HS-stressed cells. DREB2A up-regulated genes were classified into three groups based on their expression patterns: genes induced by HS, genes induced by drought stress, and genes induced by both HS and drought stress. DREB2A up-regulated genes were down-regulated in DREB2A knockout mutants under stress conditions. Thermotolerance was significantly increased in plants overexpressing <jats:italic>DREB2A CA</jats:italic> and decreased in <jats:italic>DREB2A</jats:italic> knockout plants. Collectively, these results indicate that DREB2A functions in both water and HS-stress responses. </jats:p>

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