Natural product chelerythrine induces plant resistance through activating defensive reactions.

BACKGROUND In the realm of agricultural pest management, the stability of the ecosystem is gaining growing significance. Promoting robust plant growth to enhance disease resistance and reduce the likelihood of pest infestations is an effective approach for achieving sustainable agricultural development and minimizing the use of chemical pesticides. Natural botanical products, characterized by their environmental friendliness and biosafety for non-target organisms, hold great potential as plant resistance inducers. RESULTS This study systematically evaluated the resistance-inducing capability and molecular mechanism of Chelerythrine. At a concentration of 0.05 mg mL-1, Chelerythrine demonstrated a good protective efficacy against the tomato brown rugose fruit virus (ToBRFV), with an efficacy of 65.08%, which is comparable to the positive control Ningnanmycin. Mechanistic analyses revealed that Chelerythrine-mediated resistance involves coordinated activation of: (i) reactive oxygen species (ROS) signaling, (ii) mitogen-activated protein kinase (MAPK) cascade, (iii) salicylic acid/jasmonic acid (SA/JA) defense pathways, and (iv) pathogenesis-related (PR) gene expression. Moreover, Chelerythrine demonstrated broad-spectrum resistance against Botrytis cinerea, Pseudomonas syringae, and ToBRFV in tomato plants. CONCLUSION Our findings position Chelerythrine as a promising multi-pathogen resistance inducer for integrated disease management in tomato plants. The elucidated mechanism provides a theoretical framework for developing next-generation plant immunity activators from botanical sources, potentially contributing to sustainable agricultural practices through reduced agrochemical inputs. © 2025 Society of Chemical Industry.