OsGSTT3 regulates seed germination by modulating reactive oxygen species homeostasis in rice

The glutathione S-transferase family gene OsGSTT3 in rice regulates seed germination by modulating reactive oxygen species (ROS) homeostasis. The relative expression levels of ROS scavenging-related genes were changed. Seed germination is a complex physiological process regulated by both internal and external factors. Glutathione S-transferases (GSTs), a critical class of antioxidant enzymes, play key roles in plant responses to environmental stress. However, their molecular regulatory mechanisms in rice seed germination remain largely unexplored. In this study, we identified OsGSTT3 as a key regulator of seed germination in rice. Both OsGSTT3 overexpression and knockout lines exhibited delayed germination speeds compared with wild-type (WT) plants. RT-qPCR analysis revealed that OsGSTT3 is highly expressed in seeds and during germination, with its expression modulated by hydrogen peroxide (H₂O₂) and diphenyleneiodonium chloride (DPI). Exogenous H₂O₂ and DPI treatments further confirmed that reactive oxygen species (ROS) levels are critical determinants of germination in OsGSTT3 transgenic lines. Measurements of endogenous H₂O₂ revealed significantly reduced levels in overexpression lines and increased levels in knockout lines relative to WT. Additionally, OsGSTT3 regulates ROS homeostasis during germination by modulating the expression of ROS scavenging-related genes. Collectively, our findings establish OsGSTT3 as a key regulator of seed germination via ROS homeostasis, providing novel insights into the molecular mechanisms of rice germination and offering a potential genetic resource for improving rice germplasm.