The Peach (Prunus persica) Defensin PpDFN1 Displays Antimicrobial Activity against Fungal Pathogens through Specific Lipid Binding and Membrane Permeabilization

Plant defensins are a large family of small, cationic, cysteine rich peptides playing crucial role in the plant innate immunity. These small proteins are secreted into the extracellular environment upon recognition of a signal sequence, which is typically located N-terminal to the mature peptide. Mature defensins are fairly divergent in primary sequence, with the exception of the typical conserved cysteine pattern. Defensins are very interesting targets for agrobiotechnology applications because of their broad range antimicrobial activity against important plant fungal pathogens. Here we report on the expression of PpDFN1 (Prunus persica DFN1) gene in peach flower and fruits at different ripening stages. The recombinant PpDFN1 was expressed in E. coli and purified and its antimicrobial activity characterized, together with its localization on the surface of fungal hyphae and its interaction with fungal membranes.