Journal of Plant Research

, Volume 125, Issue 6, pp 793–804 | Cite as

Zn tolerance of novel Colocasia esculenta metallothionein and its domains in Escherichia coli and tobacco

  • Yeon-Ok Kim
  • Yoon Gyo Lee
  • Darshan H. Patel
  • Ho Myeong Kim
  • Sung-Ju Ahn
  • Hyeun-Jong Bae
Regular Paper


Contrary to extensive researches on the roles of metallothioneins (MTs) in metal tolerance of animals, the roles of plant MTs in metal tolerance are largely under investigation. In this study, we evaluated the functional role of type 2 MT from Colocasia esculenta (CeMT2b) in Zn tolerance of tobacco and E. coli cells. Under Zn-stress conditions, transgenic tobacco overexpressing CeMT2b displayed much better seedling growth, a significant decrease in the levels of H2O2 and an increase in Zn accumulation compared with the wild type. Overexpression of CeMT2b in E. coli greatly enhanced Zn tolerance and Zn accumulation under Zn stresses compared with control cells. CeMT2b bound 5.38 ± 0.29 atoms of Zn per protein. To identify a structural domain of CeMT2b for Zn binding, we investigated the growth of E. coli expressing each of the N-terminal, C-terminal, and central linker domains or a CNC motif deletion from the C-terminus of full-length CeMT2b. The results showed that the CNC motif is required for Zn tolerance, and the N-terminal domain is more effective in Zn tolerance than the C-terminal domain. Taken together, our results provide direct evidence for functional contributions of CeMT2b in Zn tolerance of tobacco and E. coli cells.


Metal binding domain MT2b ROS scavenge Seedling growth Transgenic tobacco Zn/protein ratio 



This work was supported by Priority Research Centers Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education, Science and Technology (Project No. 2011-0018393) to H.-J. Bae and World Class University project of the Ministry of Science and Technology of Korea (R31-2009-000-20025-0) to H.-J. Bae.

Supplementary material

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Supplementary material 1 (PDF 81 kb)


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Copyright information

© The Botanical Society of Japan and Springer 2012

Authors and Affiliations

  • Yeon-Ok Kim
    • 1
  • Yoon Gyo Lee
    • 2
  • Darshan H. Patel
    • 3
  • Ho Myeong Kim
    • 2
  • Sung-Ju Ahn
    • 4
  • Hyeun-Jong Bae
    • 4
  1. 1.Bio-Energy Research InstituteChonnam National UniversityGwangjuRepublic of Korea
  2. 2.Department of Forest Products and Technology (BK21 Program)Chonnam National UniversityGwangjuRepublic of Korea
  3. 3.Department of Biochemistry, PDPIASCharotar University of Science and TechnologyChangaIndia
  4. 4.Department of Bioenergy Science and Technology, Bio-Energy Research InstituteChonnam National UniversityGwangjuRepublic of Korea

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