The NIN-Like Protein OsNLP2 Negatively Regulates Ferroptotic Cell Death and Immune Responses to in Rice.

Nodule inception (NIN)-like proteins (NLPs) have a central role in nitrate signaling to mediate plant growth and development. Here, we report that OsNLP2 negatively regulates ferroptotic cell death and immune responses in rice during infection. OsNLP2 was localized to the plant cell nucleus, suggesting that it acts as a transcription factor. OsNLP2 expression was involved in susceptible disease development. knockout mutants exhibited reactive oxygen species (ROS) and iron-dependent ferroptotic hypersensitive response (HR) cell death in response to . Treatments with the iron chelator deferoxamine, lipid-ROS scavenger ferrostatin-1, actin polymerization inhibitor cytochalasin A, and NADPH oxidase inhibitor diphenyleneiodonium suppressed the accumulation of ROS and ferric ions, lipid peroxidation, and HR cell death, which ultimately led to successful colonization in mutants. The loss-of-function of OsNLP2 triggered the expression of defense-related genes including , , , and in mutants. mutants exhibited broad-spectrum, nonspecific resistance to diverse strains. These combined results suggest that OsNLP2 acts as a negative regulator of ferroptotic HR cell death and defense responses in rice, and may be a valuable gene source for molecular breeding of rice with broad-spectrum resistance to blast disease.