Abstract
Rice (Oryza sativa) is a typical chilling-sensitive crop. Exposure to low temperature induces production of reactive oxygen species (ROS) such as H2O2, which results in oxidative damage to nucleic acids, lipids and proteins. Previously, we demonstrated that overexpression of a wheat catalase gene in rice plants results in a high catalase activity and delayed leaf wilting during chilling. However, the mechanism of chilling tolerance acquisition is still unknown. Here, we hypothesize that catalase-overexpressing rice plants prevent proteins involved in chilling tolerance from oxidation caused by ROS and, consequently, increase chilling tolerance. Electrolyte leakage test revealed that, during chilling, transgenic plants showed less damage to roots and leaves than wild type. Moreover, western blot analyses showed chilling-induced oxidation to proteins suppressed in transgenic plants. These results suggest that suppression of oxidized proteins in transgenic plants may be associated with acquisition of chilling tolerance.
