1. The role of the kinase OXI1 in cadmium- and copper-induced molecular responses in Arabidopsis thaliana.
- Author
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SMEETS, KAREN, OPDENAKKER, KELLY, REMANS, TONY, FORZANI, CELINE, HIRT, HERIBERT, VANGRONSVELD, JACO, and CUYPERS, ANN
- Subjects
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MITOGEN-activated protein kinases , *EFFECT of cadmium on plants , *SUPEROXIDE dismutase , *OXYLIPINS , *EFFECT of copper on plants , *LIPOXYGENASES , *PLANT defenses - Abstract
The hypothesis that mitogen-activated protein kinase ( MAPK) signalling is important in plant defences against metal stress has become accepted in recent years. To test the role of oxidative signal-inducible kinase ( OXI1) in metal-induced oxidative signalling, the responses of oxi1 knockout lines to environmentally realistic cadmium ( Cd) and copper ( Cu) concentrations were compared with those of wild-type plants. A relationship between OXI1 and the activation of lipoxygenases and other initiators of oxylipin production was observed under these stress conditions, suggesting that lipoxygenase-1 may be a downstream component of OXI1 signalling. Metal-specific differences in OXI1 action were observed. For example, OXI1 was required for the up-regulation of antioxidative defences such as catalase in leaves and Fe-superoxide dismutase in roots, following exposure to Cu, processes that may involve the MEKK1- MKK2- WRKY25 cascade. Moreover, the induction of Cu/Zn superoxide dismutases in Cu-exposed leaves was regulated by OXI1 in a manner that involves fluctuations in the expression of miRNA398. These observations contrast markedly with the responses to Cd exposure, which also involves OXI1-independent pathways but rather involves changes in components mediating intracellular communication. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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