Fludioxonil loaded liposomes vs Botrytis cinerea: a new perspective for sustainable management of grey mold

Botrytis cinerea is a ubiquitous phytopathogenic fungus responsible for grey mold, affecting worldwide important crops in the field and in postharvest. Different strategies are used to manage B. cinerea, but chemicals remain the most consolidated. To address the challenge of sustainable agriculture, nanotechnology has been applied to improve fungicide delivery. Here, liposomes loaded with the fungicide Fludioxonil (FLUD) were developed through the micelle-to-vesicle transition method or extrusion technique. Three types of vesicle composition (plain, PEG-coated, and cationic vesicles) were compared for Encapsulation Yields, Drug Loading Content, and Zeta potentials. The extruded and PEGylated liposomes were the most stable over time and, together with the Cationic ones, showed a significantly prolonged FLUD release capacity. Liposomes' biological activity was evaluated on B. cinerea conidial germination, germ tube elongation, and colony radial growth. In in vitro assay with different concentrations of FLUD technical grade or FLUD-loaded liposomes, the Extruded PEGylated liposomes were the optimal compromise for active substance release and pathogen control. Following a slight control of conidial germination, although less effective than FLUD (22.7% at 0.3 μg·ml-1), the formulation showed higher effectiveness than FLUD in the subsequent stages of germ tube elongation and mycelial growth (respectively 7.7% and 68% at 0.01 μg·ml-1). By improving the fungicide stability, the liposomal formulation can increase its persistence, extend the application interval, and target distinct stages of pathogen development. Furthermore, the liposome's ability to adhere to membranes mediates a targeted release, improving effectiveness, and should represent a new tool for sustainable control strategies.