Mechanistic insights into the synergistic antimicrobial activity of nanodelivered sodium polysulfide as a sustainable strategy to combat Xanthomonas pathogens

Nanopesticides offer a promising avenue for crop management by enhancing efficacy over their conventional counterparts. Advances in managing surface-restricted plant pathogens have been reported using magnesium-based nanomaterials, but their role as delivery systems for conventional pesticides remains unexplored. This study introduces Nano-Magnesium Hydroxide (MgSol) as a delivery platform for Sodium Polysulfide (NaPs), elucidates the physicochemical interactions between the treatments, determines the ramifications of the changes on their antimicrobial mode of action, and evaluates the plant's response. A comprehensive investigation using theoretical and experimental approaches provides insights into the adsorption of polysulfide ions onto Mg(OH)₂ surfaces, leading to particle agglomeration and enhanced polysulfide stability. Temporal monitoring demonstrates that nanodelivered NaPs remain chemically active 12 times longer than the conventional counterpart. Antimicrobial assays confirm that nanodelivered NaPs possesses synergistic bactericidal activity, achieving an 8-fold greater potency than its components. Mechanistic studies unveil that nanodelivered NaPs drives intracellular peroxidation, leading to membrane disruption. Lastly, conditions for plant and seed biocompatibility are identified, with foliar residue studies showing an improvement in Mg deposition. Altogether, these findings showcase the potential of nano-enabled agrochemical delivery via inorganic nanoparticles to sustainably mitigate crop loss, supporting food security amidst rising global demands.