A pH-responsive multimodal antimicrobial nanosystem for plant disease control.

Nanocarrier-based controlled-release technologies significantly enhance the effective utilization rate of pesticides. Multimodal synergistic antimicrobial strategies that disrupt multiple pesticide resistance pathways are considered promising for plant disease management. In this study, a novel pH-responsive pesticide delivery system based on kasugamycin-intercalated ZnFe hydrotalcites (KAS-Zn-Fe HTlc) was developed to achieve synergistic antibacterial effects. KAS-Zn-Fe HTlc was synthesized via a co-precipitation method. Its physicochemical properties were characterized using SEM, XRD, UV-vis, and FT-IR. The loading capacity, controlled release kinetics, thermal stability, photostability, antibacterial activity, and crop safety were evaluated. KAS-Zn-Fe HTlc exhibited rapid release of KAS and Zn2+ under acidic conditions. KAS-Zn-Fe HTlc enhanced the thermal stability of KAS and significantly reduced its photodegradation during the initial phase. Bioactivity assays demonstrated that KAS-Zn-Fe HTlc exhibited 32-fold and 2-fold increased antibacterial activity against Clavibacter michiganensis subsp. michiganensis and Pseudomonas syringae pv. lachrymans, respectively, when compared to KAS. No phytotoxicity was observed in tomato seedlings treated with KAS-Zn-Fe HTlc. Therefore, KAS-Zn-Fe HTlc holds significant potential for synergistic antimicrobial functions and offers a sustainable approach to plant disease control.