Mitogen-activated protein kinase kinase 5 (MKK5)-mediated signalling cascade regulates expression of iron superoxide dismutase gene in Arabidopsis under salinity stress

摘要: Superoxide dismutases (SODs) are involved in plant adaptive responses to biotic and abiotic stresses but the upstream signalling process that modulates their expression is not clear. Expression of two iron SODs, FSD2 FSD3, was significantly increased Arabidopsis response NaCl treatment blocked transgenic MKK5-RNAi plant, mkk5. Using an assay system for transient protoplasts, it found mitogen-activated protein kinase 5 (MKK5) also activated salt stress. Overexpression MKK5 wild-type plants enhanced tolerance treatments, while mkk5 mutant exhibited hypersensitivity stress germination on salt-containing media. Moreover, another kinase, MPK6, MKK5-mediated superoxide dismutase (FSD) pathway The activity MPK6 totally turned off mkk5, whereas MPK3 only partially blocked. interacted with MEKK1 salt-induced FSD pathway. These data suggest FSD3 expressions influenced by via MKK5-MPK6-coupled signalling. This MAP cascade (MEKK1, MKK5, MPK6) mediates dismutases.