Isolation, Identification and Characteristics of a Bacterium with Extensive Antifungal Activity from a Corn Leaf Spot

Abstract:

A strain of bacterium (CGMCC No. 1982) was isolated from a corn leaf spot infected by Bipolaris maydis. The strain exhibited extensive antagonistic effect on quite a number of plant pathogenic fungi such as Bipolaris maydis, Magnaporthe grisea, Fusarium graminearum and so on. The strain was identified as Bacillus subtillis based on the 16S rDNA sequence homology, and the physiological and biochemical characteristics and morphological observation. The antagonistic substances prepraed by adding 60% saturation of ammonium sulfate to cultivating medium of the strain exhibited higher antifungal activity. The physical and chemical character of the antagonists was tested using Bipolaris maydis as indicator. The results suggested that the antagonists were of thermal stability and acidic-basic stability. However, the antagonists were sensitive to protease and chloroform, partially sensitive to Ultraviolet. Therefore, the strain has a bright developmental prospect as a novel biocontrol bacterium.

Key words:Bacillus subtillis, Inhibition, 16S rDNA sequence, Fungicide