The OsSRLD-OsIMα1a-OsWRKY53 and OsSRLD-OsDIP1 Modules Balance Disease Resistance and Drought/Salt Tolerance in Rice

Understanding the molecular mechanisms underlying plant responses to various stresses is crucial for improving crop productivity under stressful conditions. However, how plants prioritize the activation of pathways to balance disease resistance with drought and salt tolerance remains unclear. Here, we identify two regulatory modules centered on the rice protein OsSRLD, which negatively regulates disease resistance and positively regulates drought/salt tolerance. Upregulation of OsSRLD increases ABA content and reduces ROS levels under both normal and stressed conditions, suggesting its involvement in ABA signaling and ROS homeostasis. As an E3 ligase, OsSRLD interacts with OsIMα1a (a positive regulator of disease resistance) and promotes its ubiquitination and degradation via the 26S proteasome. Additionally, OsIMα1a interacts with OsWRKY53 (a positive regulator of disease resistance but a negative regulator of salt tolerance), thereby promoting the nuclear accumulation of OsWRKY53. Consistently, both overexpression of OsSRLD and knockout of OsIMα1a resulted in downregulation of OsWRKY53-activated genes and upregulation of OsWRKY53-inactivated genes. Furthermore, OsSRLD interacts with and stabilizes OsDIP1 (a positive regulator of drought and salt tolerance) via an E3 ligase-independent pathway. Together, our findings reveal that OsSRLD-OsIMα1a-OsWRKY53 and OsSRLD-OsDIP1 modules balance disease resistance and drought/salt tolerance through both E3 ligase-dependent and E3 ligase-independent pathways.