Virtual screening of quorum sensing inhibitors against Pseudomonas tolaasii and its application in the preservation of mushroom (Agaricus bisporus)

Pseudomonas tolaasii ( P. tolaasii ) is a main bacterial pathogen responsible for mushroom brown spot disease, and there is an urgent need for safer, more effective biocontrol solutions. The study focused on LuxI/R proteins, key quorum sensing (QS) regulators in P. tolaasii , by predicting their three-dimensional structures to screen potential quorum sensing inhibitors (QSIs). Thirteen kinds of natural plant essential oils (EOs) were identified as QSIs, and their QS activities were further determined. A thorough evaluation of the inhibitory effects of six kinds of EOs with QS activity on the QS phenotype of P. tolaasii was conducted, revealing that cinnamon essential oil (CEO) exhibited a substantial QS inhibitory effect on P. tolaasii . At 0.2 mg/mL, CEO significantly reduced bacterial motility, virulence factor secretion, and biofilm formation. Molecular docking and molecular dynamics simulations showed that cinnamaldehyde, the main bioactive compound in CEO, formed stable interactions with LuxI and LuxR proteins through van der Waals forces and electrostatic interactions. In simulated aqueous environments, the LuxI-cinnamaldehyde complex maintained its structural integrity over 25 ns, primarily due to the stabilizing effects of van der Waals forces and electrostatic interactions. In practical applications, CEO preservation pads effectively delayed mushroom spoilage and preserved postharvest quality. This research provides a reference for the screening and application of natural food QSIs.