| Summary: | 碩士 === 國立成功大學 === 生命科學系碩博士班 === 96 === Eukaryotic mitogen-activated protein kinase (MAPK) signalling pathway acts downstream of receptors or sensors to transduce extracellular stimuli, including abiotic and biotic stresses, into adaptive, intracellular responses. A MAPK pathway minimally consists of a MAPKKK-MAPKK-MAPK module. The Arabidopsis thaliana MKK1 and MKK2 MAP kinase kinases have been implicated in biotic and abiotic stress responses, but the role of the MKK2 in metal signalling pathway is unknown.
In this study, we evaluated the role of the MKK2 in regulating copper stress responses in Arabidopsis . Overexpressing of MKK2 enhanced Arabidopsis resistance to copper stress. When wild type, mkk2 and MKK2-EE4 seedlings were subjected to copper treatment for 7 days, the root elongation of MKK2-EE4 plants were significantly higher than the wild type and mkk2 mutant plants. Copper induced cell death was reduced and reactive oxygen species (ROS) production was accumulated in MKK2-EE4 plants compared with wild type and mkk2 mutant plants. In addition, 200 μM copper supply resulted in higher copper concentration in mkk2 mutant roots as compared to wild type, and the copper concentration in MKK2-EE4 roots was lower than the wild type plants. Taken together these results demonstrate that MKK2 signalling is involved in Arabidopsis copper tolerance and the uptake and storage of copper are also affected by this signalling pathway.
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