Functions of Rice E3 Ubiquitin Ligases in Response to Environmental Stress and in Regulating Grain Size

The ubiquitin-proteasome system involves three types of enzymes (E1, E2, and E3) that promote protein ubiquitination and degradation. Among these, the E3 ubiquitin ligase mediates substrate specificity. In rice, over 1 500 E3 enzymes have been identified, playing diverse roles in growth, developmental processes, and responses to biotic and abiotic stresses. In recent years, significant progress has been made, with some breakthroughs in regulating disease resistance. Here, we summarize the roles of rice E3 ubiquitin ligases in responding to biotic and abiotic stresses, as well as their functions in regulating key agronomic traits such as seed size. Additionally, future research directions are discussed. This review aims to facilitate further studies on E3 ubiquitin ligases in rice.