SlHBP2 enhances tomato defense through OPDA signaling by boosting antioxidant machinery and regulating ROS in Pseudomonas infection

To sustainably meet the growing global demand for food, the conventional reliance on potentially harmful chemicals for pathogen control is transitioning to more sustainable methods that enhance plant innate immunity. Enhancing plant defenses through innovative strategies, such as utilizing antimicrobial proteins and peptides (APPs), offers an eco-friendly approach to combat significant agricultural pathogens by inducing resistance in plants. Our findings demonstrate that tomato plants treated with Solanum lycopersicum heme-binding protein 2 (SlHBP2), an apoplastic heme-binding protein with antimicrobial activity exhibited fewer disease symptoms and a lower bacterial population compared to control plants after infection with Pseudomonas syringae pv. tomato DC3000 (Pst). Remarkably, SlHBP2 treatment stimulates 12-oxo-phytodienoic acid (OPDA) production, triggering induced systemic resistance in SlHBP2-treated plants. This systemic response boosts the overall resistance of SlHBP2-treated tomato plants to Pst by activating the antioxidant machinery. This activation results in a notable decrease in rapid reactive oxygen species (ROS) production post-inoculation by Pst. In conclusion, SlHBP2 contributes novel strategies for crop protection by enhancing OPDA-mediated defense responses, strengthening plant immunity while mitigating oxidative stress and cellular damage during Pst infection.