Ethanol Enhances High-Salinity Stress Tolerance by Detoxifying Reactive Oxygen Species in Arabidopsis thaliana and Rice

High-salinity stress considerably affects plant growth and crop yield. Thus, developing techniques to enhance high-salinity stress tolerance in plants is important. In this study, we revealed that ethanol enhances high-salinity stress tolerance in and rice. To elucidate the molecular mechanism underlying the ethanol-induced tolerance, we performed microarray analyses using seedlings. Our data indicated that the expression levels of 1,323 and 1,293 genes were upregulated by ethanol in the presence and absence of NaCl, respectively. The expression of reactive oxygen species (ROS) signaling-related genes associated with high-salinity tolerance was upregulated by ethanol under salt stress condition. Some of these genes encode ROS scavengers and transcription factors (e.g., and ). A RT-qPCR analysis confirmed that the expression levels of and as well as and , which encode cytosolic ascorbate peroxidases (APX), were higher in ethanol-treated plants than in untreated control plants, when exposure to high-salinity stress. Additionally, cytosolic APX activity increased by ethanol in response to salinity stress. Moreover, histochemical analyses with 3,3'-diaminobenzidine (DAB) and nitro blue tetrazolium (NBT) revealed that ROS accumulation was inhibited by ethanol under salt stress condition in and rice, in which DAB staining data was further confirmed by Hydrogen peroxide (H O ) content. These results suggest that ethanol enhances high-salinity stress tolerance by detoxifying ROS. Our findings may have implications for improving salt-stress tolerance of agriculturally important field-grown crops.