An antifungal peptide from passion fruit (Passiflora edulis) seeds with similarities to 2S albumin proteins

An actual worldwide problem consists of an expressive increase of economic losses and health problems caused by fungi. In order to solve this problem, several studies have been concentrating on the screening of novel plant defence peptides with antifungal activities. These peptides are commonly characterized by having low molecular masses and cationic charges. This present work reports on the purification and characterization of a novel plant peptide of 5.0 kDa, Pe-AFP1, purified from the seeds of passion fruit (Passiflora edulis). Purification was achieved using a Red-Sepharose Cl-6B affinity column followed by reversed-phase chromatography on Vydac C18-TP column. In vitro assays indicated that Pe-AFP1 was able of inhibiting the development of the filamentous fungi Trichoderma harzianum, Fusarium oxysporum, and Aspergillus fumigatus with IC50 values of 32, 34, and 40 microg ml(-1), respectively, but not of Rhyzoctonia solani, Paracoccidioides brasiliensis and Candida albicans. This protein was also subjected to automated N-terminal amino acid sequence, showing high degree of similarities to storage 2S albumins, adding a new member to this protein-defence family. The discovery of Pe-AFP1 could contribute, in a near future, to the development of biotechnological products as antifungal drugs and transgenic plants with enhanced resistance to pathogenic fungi.