Enhanced Control of Tomato Bacterial Wilt Using a Triple-Responsive Nanopesticide with Self-Supplying Reactive Oxygen Species

Abstract

Tomato production, a vital component of global horticulture, is threatened by bacterial wilt caused by Ralstonia solanacearum. To address this, a triple-responsive nanoplatform (Ber@MON@CuO₂@HPC) integrating berberine chloride (Ber), copper peroxide (CuO₂) nanoparticles, mesoporous organosilica nanoparticles (MONs), and hydroxypropyl cellulose (HPC) encapsulation is presented. Ber@MON@CuO₂@HPC enables efficiently controlled release and self-supply of reactive oxygen species (ROS), enhancing antibacterial efficacy. The system demonstrates pH-, glutathione-, and cellulase-responsive release, ensuring on-demand delivery of berberine chloride with a loading capacity of 12.0%. HPC encapsulation significantly reduces the contact angle, improving foliar adhesion and retention. In vitro antibacterial assays reveal that despite an 88% reduction in the berberine chloride dosage, Ber@MON@CuO₂@HPC achieves a 1.84-fold increase in efficacy compared with that using free berberine chloride. Mechanistically, the nanoplatform induces ROS-mediated bacterial membrane disruption, cytoplasmic leakage, and nucleoid degradation, accompanied by a significant downregulation of key R. solanacearum pathogenesis (phcA, hrpB, pehC, and epsE)- and mobility (filA)-related genes. Greenhouse experiments further validate its effectiveness in reducing disease severity. Moreover, MON@CuO₂@HPC exhibits excellent biocompatibility with no adverse effects on tomato plant growth. This study presents a sustainable nanopesticide strategy combining stimuli-responsive controlled-release and self-supplying ROS antibacterial mechanisms, offering an effective approach for plant disease management while minimizing pesticide input.