Unifying Gibberellin pathway modulation, anti-biofilm, and foliar adhesion in a stimuli-responsive supramolecular complex for plant growth promotion and bacterial disease control

Controlling plant bacterial diseases is challenged by the scarcity of effective bactericides, their poor foliar adhesion, and non-target toxicity. The situation is worsened when pathogens form resilient biofilms, effectively armoring themselves against bactericidal treatments. To break this cycle, we present a stimuli-responsive nanopesticide delivery system, engineered via highly active bactericide design and supramolecular self-assembly. In this study, initially, a highly bioactive 1,3,4-oxadiazole-modified morpholine salt (OM) was designed and subsequently encapsulated via host-guest interaction with cucurbit[7]uril (CB[7]), leading to the self-assembly of lamellar structures approximately 100 nm in size (OM@CB[7]). These supramolecular aggregates fully realized the benefits of the supramolecular encapsulation strategy, exhibiting excellent foliar adhesion (with a 90% increase in retention), reduced phytotoxicity, and a remarkable growth-promoting effect through activation of gibberellin biosynthesis, together with systemic coordinated enrichment of auxin, jasmonic acid, and photosynthesis pathways. Upon introduction of the competitive stimulus, OM was released in a controlled manner, demonstrating potent bactericidal efficacy, suppression of bacterial virulence, and robust anti-biofilm activity. At a concentration of 30 μ g mL -1 , the system achieved over 90% reduction in mature biofilm biomass. In vivo pot trials confirmed its significant efficacy against rice bacterial leaf blight, with a curative activity of 55.2% at 200 μ g mL -1 , outperforming the commercial bactericide thiodiazole-copper (40.1%). The stimuli-responsive nanopesticide delivery strategy achieves the synergy of bactericidal activity, biofilm eradication, controlled release, toxicity reduction, and growth promotion, providing a new paradigm for the development of safe, efficient, and multifunctional intelligent pesticides.