Glucohexaose-induced protein phosphatase 2C regulates cell redox status of cucumber seedling.

Protein Phosphatase 2C (PP2C) is an important phosphatase-like protein in eukaryotic organisms that can negatively regulate protein kinase cascade abscisic acid (ABA) signal system through phosphorylation and carry out vital roles in various cell processes. The previous study indicated that the accumulation of reactive oxygen species (ROS) is a part of mechanism of glucohexaose-induced resistance in cucumber cotyledons, and CsPP2C80s might play a crucial role in processes related to ROS produce and signal transduction. To identify the mechanism of CsPP2C80s involved in glucohexaose and ABA signaling regulating cell redox status, the effects of glucohexaose and ROS inhibitor pretreatment on endogenous ABA content and ABA signaling genes expression levels of cucumber seedlings were analysed. These results suggest that cucumber CsPP2C80s are involved in ROS accumulation and ABA signal transduction pathway induced by glucohexaose, CsPP2C80s play a positive regulatory role in process of ABA combined with ABA receptors (PYLs) to activate SNF1-related protein kinases 2 (SnRK2s) and regulate NADPH oxidase to produce extracellular hydrogen peroxide (H2O2), providing unequivocal molecular evidence of PP2C-mediated ABA response mechanisms functioning in cell redox status induced by glucohexaose.