J Integr Plant Biol. ›› 2018, Vol. 60 ›› Issue (4): 310-322.DOI: 10.1111/jipb.12618

• Molecular Physiology • Previous Articles     Next Articles

OTS1‐dependent deSUMOylation increases tolerance to high copper levels in Arabidopsis

Erbao Zhan1†, Huapeng Zhou1†*, Sha Li1, Lei Liu2, Tinghong Tan1 and Honghui Lin1*   

  1. 1Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China
    2State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
  • Received:2017-10-31 Accepted:2017-11-30 Published:2018-04-20
  • About author:These authors contributed equally to this work.
    **Correspondences: Email: Huapeng Zhou (zhouhuapeng@scu.edu.cn); Honghui Lin (hhlin@scu.edu.cn, Dr. Zhou and Dr. Lin are fully responsible for the distribution of all materials associated with this article)


The conjugation of SUMO (small ubiquitin‐like modifier) to protein substrates is a reversible process (SUMOylation/deSUMOylation) that regulates plant development and stress responses. The essential metal copper (Cu) is required for normal plant growth, but excess amounts are toxic. The SUMO E3 ligase, SIZ1, and SIZ1‐mediated SUMOylation function in plant tolerance to excess Cu. It is unknown whether deSUMOylation also contributes to Cu tolerance in plants. Here, we report that OTS1, a protease that cleaves SUMO from its substrate proteins, participates in Cu tolerance in Arabidopsis thaliana (Arabidopsis). OTS1 loss‐of‐function mutants (ots1‐2 and ots1‐3) displayed increased sensitivity to excess Cu. Redox homeostasis and the balance between SUMOylation and deSUMOylation were disrupted in the ots1‐3 mutant under excess Cu conditions. The ots1‐3 mutant accumulated higher levels of Cu in both shoots and roots compared to wild type. Specific Cu‐related metal transporter genes were upregulated due to the loss‐of‐function of OTS1, which might explain the high Cu levels in ots1‐3. These results suggest that the SUMOylation/deSUMOylation machinery is activated in response to excess Cu, and modulates Cu homeostasis and tolerance by regulating both Cu uptake and detoxification. Together, our findings provide insight into the biological function and regulatory role of SUMOylation/deSUMOylation in plant tolerance to Cu.

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