[Objective] With a strain of endophytic antagonistic bacteria with good disease control efficacy in pot as trial material,the paper was to explore the antagonistic mechanism of siderophore against Fusarium oxysporum.[Method] Whether the strain produced siderophore and its fluorescent property was judged by MSA（Modified Sugar-Aspartic acid） plate.The siderophore activity of strains in liquid MSA medium was determined through the absorbance values at particular wavelength.The inhibition effects of it siderophore against F.oxysporum under different concentrations of Fe3＋ were compared.Then the strain was preliminarily identified based on morphological,physiological and biochemical characteristics [Result] The fluorescent siderophore produced by the endophytic bacteria in MSA medium had a strong inhibition effect against F.oxysporum.With the increasing concentration of Fe3＋,the inhibition effect against the pathogen weakened.The preliminary analysis showed these strains belonged to Bacillus.[Conclusion] Bacillus could compete the absorption of Fe3＋ by secreting siderophore to inhibit the growth of F.oxysporum.
