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Plants acquire nutrients, including heavy metals, form soil. The in-depth understanding of the action mechanisms of heavy metal homoeostasis is essential for future materialization of phytoremediation and biofortification. A balanced heavy metal homeostasis relies on seamless integration of uptake, transport and sequestration/detoxification. However, this line of research is still in its juvenile stage. In addition, physiological impacts under various metal conditions are largely unknown. To fill the gap in knowledge of heavy metal homeostasis, my lab started the study of hyperaccumulators. In addition to revealing genes related to classical heavy metal homeostasis, we have learned of the critical strategies Arabidopsis halleri, a heavy metal accumulator, uses for Zn tolerance and accumulation. We found that the maintenance of Fe homeostasis is most important for plants to survive in the heavy metal–rich habitat. The mechanisms include adjusted gene expression for Fe acquisition and “protectant” secretion to protect against toxicity in an excess Zn environment. Researches derived from this hypothesis will be discussed in the seminar. Nevertheless, we made additional efforts to study Fe homeostasis and functions to understand the importance of the metal in the defense against heavy metal stress. We hope that our discoveries made in the past few years could expand the knowledge in key steps of heavy metal homeostasis, including the processes of acquisition, detoxification and the physiological impacts of metals. 1. M. Tsednee, S.-C. Yang, D.-C. Lee and K.-C. Yeh* (2014) Root-secreted nicotianamine from Arabidopsis halleri facilitates zinc hypertolerance by regulating zinc bioavailability. Plant Physiology in press: 2. L.-J. Shin, J.-C. Lo, G.-H. Chen, J. Callis, H. Fu and K.-C. Yeh* (2013) IRT1 DEGRADATION FACTOR 1, a RING E3 ubiquitin ligase, regulates the degradation of IRON-REGULATED TRANSPORTER 1 in Arabidopsis. Plant Cell 25: 3039-3051; 3. Y.-Y. Chen, Y Wang, L.-J. Shin, J.-F. Wu, V. Shanmugam, M. Tsednee, J.-C. Lo, C.-C. Chen, S.-H. Wu and K.-C. Yeh* (2013) Iron is involved in the maintenance of circadian period length in Arabidopsis. Plant Physiology 161: 1409-1420; 4. V. Shanmugam, M. Tsednee and K.-C. Yeh* (2012) ZINC TOLERANCE INDUCED BY IRON 1 reveals the importance of glutathione in the cross homeostasis between zinc and iron in Arabidopsis thaliana. Plant Journal 69 (6): 1006-1017 第111回 Plant Science Seminar Heavy metal homeostasis in plants and application 日時 ： ９月８日 (月) １３：００〜１４：００ 場所 ： 農学部総合研究棟一階多目的室（Ｗ１０９） Dr. Kuo-Chen Yeh Agricultural Biotechnology Research Center, Academia Sinica,Taipei, Taiwan Plant Science Seminar 北大内で植物科学を研究している（特に）若い人たちの交流促進 の場を提供するためのセミナーです。Yeh氏は重金属輸送の研究で注目を集める気鋭の研 究者です。9月8-9日にはDiscussionの時間も設けますので希望の方はご連絡ください。 世話人： 高野順平（内線：3888）
