RESUMO
Both mitogen-activated protein kinase (MAPK) cascades and reactive oxygen species (ROS) are critical to signaling in eukaryotes. Cadmium induces MAPK activation and ROS production in plants. This study aims to identify specific MAPKs activated by CdCl2 in maize roots, and examine the relationship between MAPK activation and ROS production under CdCl2 treatment. Using in-gel kinase assays, immunoprecipitation, and immunoblot analysis, we identified 43 and 45â¯kDa ERK-like MAPKs in response to CdCl2. Further analysis revealed that ZmMPK3-1 and ZmMPK6-1 correspond to the 43 and 45â¯kDa MAPKs, respectively. In addition, CdCl2 induced ROS production prior to the activation of ZmMPK3-1 and ZmMPK6-1. Inhibition of ROS attenuated Cd-activation of ZmMPK3-1 and ZmMPK6-1, whereas inhibition of MAPK signaling did not disturb Cd-induced ROS production. Collectively, these results indicate that, in maize roots, cadmium stress activates ZmMPK3-1 and ZmMPK6-1 via ROS induction.
Assuntos
Cádmio/farmacologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Zea mays/metabolismo , Cloreto de Cádmio/farmacologia , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/genética , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Immunoblotting , Isoenzimas/genética , Isoenzimas/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/genética , Proteínas Quinases Ativadas por Mitógeno/genética , Proteínas de Plantas/genética , Raízes de Plantas/genética , Zea mays/genéticaRESUMO
Cold acclimation is a process used by most temperate plants to cope with freezing stress. In this process, the expression of cold-responsive (COR) genes is activated and the genes undergo physiological changes in response to the exposure to low, non-freezing temperatures and other environmental signals. The C-repeat-binding factors (CBFs) have been demonstrated to regulate the expression of many COR genes. Recent studies have elucidated the molecular mechanisms of how plants transmit cold signals from the plasma membrane to the CBFs and the results have indicated that COR genes are also regulated through CBF-independent pathways. Climate change is expected to have a major impact on cold acclimation and freezing tolerance of plants. However, how climate change affects plant cold acclimation at the molecular level remains unclear. This mini-review focuses on recent advances in cold acclimation in Arabidopsis thaliana and discusses how signaling can be potentially impacted by climate change. Understanding how plants acquire cold acclimation is valuable for the improvement of the freezing tolerance in plants and for predicting the effects of climate change on plant distribution and agricultural yield.