The conjugation of SUMO （small ubiquitin-like modifier） to protein substrates is a reversible process （SUMOylation/deSUMOylation） that regulates plant devel- opment and stress responses. The essential metal copper...The conjugation of SUMO （small ubiquitin-like modifier） to protein substrates is a reversible process （SUMOylation/deSUMOylation） that regulates plant devel- opment and stress responses. The essential metal copper （Cu） is required for normal plant growth, but excess amounts are toxic. The SUMO E3 ligase, SIZI, 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 OTSI, a protease that cleaves SUMO from its substrate proteins, participates in Cu tolerance in Arabidopsis thaliana （Arabi- dopsis）. OTS1 loss-of-function mutants （otsl-2 and otsl-3） displayed increased sensitivity to excess Cu. Redox homeostasis and the balance between SUMOylation and deSUMOylation were disrupted in the otsl-3 mutant under excess Cu conditions, The otsl-3 mutant accumulated higher levels of Cu in both shoots and roots compared to wild type. Specific Cu-related metal transporter genes were upregu- lated due to the loss-of-function of OTS% which might explain the high Cu levels in otsl-3. These results suggest that the SUMOylation/deSUMOylation machinery is acti- vated 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.展开更多
基金supported by the National Transgenic Major Project of China (2016ZX08009-003-002 to H.L.)the National Natural Science Foundation of China (31600201 to H.Z+1 种基金 31470342 and 31670235 to H.L.)the National Basic Research Program of China (2015CB150100 to H.L)
文摘The conjugation of SUMO （small ubiquitin-like modifier） to protein substrates is a reversible process （SUMOylation/deSUMOylation） that regulates plant devel- opment and stress responses. The essential metal copper （Cu） is required for normal plant growth, but excess amounts are toxic. The SUMO E3 ligase, SIZI, 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 OTSI, a protease that cleaves SUMO from its substrate proteins, participates in Cu tolerance in Arabidopsis thaliana （Arabi- dopsis）. OTS1 loss-of-function mutants （otsl-2 and otsl-3） displayed increased sensitivity to excess Cu. Redox homeostasis and the balance between SUMOylation and deSUMOylation were disrupted in the otsl-3 mutant under excess Cu conditions, The otsl-3 mutant accumulated higher levels of Cu in both shoots and roots compared to wild type. Specific Cu-related metal transporter genes were upregu- lated due to the loss-of-function of OTS% which might explain the high Cu levels in otsl-3. These results suggest that the SUMOylation/deSUMOylation machinery is acti- vated 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.
