Isolation and Identification of a Novel Antifungal Protein from a Rhizobacterium B acillus subtilis Strain F 3

B acillus subtilis strain F 3, isolated from peach rhizosphere soil, is an antifungal bacterium against many plant pathogens. In this study, the antifungal protein was isolated and purified by ammonium sulphate and chromatography, then identified by mass spectrum analysis. By sequential chromatography of S ephadex G ‐50, DEAE ‐ S ephadex A ‐25 anion exchange and S ephadex G ‐100, a fraction designated as F 3 A was isolated to show a single protein band in SDS ‐ PAGE and be antagonistic towards M onilinia fructicola . The peptide mass fingerprinting of the protein band of F 3 A had high similarity with the amino acid sequences of several flagellin protein of B . subtilis . There were seven amino acid fragments matched with the protein having the highest score, and sequence coverage was 33%. F 3 A showed a strongly inhibitory effect to the growth and sporulation of M . fructicola . There were little aerial hyphae and conidia at the antifungal zone, and the hyphae were abnormal with some cell wall collapse and several vacuoles in cells.