一株具广谱抗真菌活性细菌菌株的分离鉴定及拮抗物的理化特性

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

从玉米小斑病叶片上分离到一株细菌(CGMCC No.1982)。拮抗谱测定结果表明,该菌株对常见致病真菌均具有不同程度的拮抗作用,表现广谱抗真菌活性。对该菌株的菌落、菌体形态观察,生理生化特性分析及16S rDNA序列测定结果表明,该菌株为一株枯草芽孢杆菌。以玉米小斑病菌做为指示真菌,对拮抗物的理化特性进行了研究,结果表明,在硫酸铵饱和度为60%时获得的拮抗物沉淀具较好的抗真菌活性,并且该拮抗物对热、酸和碱较稳定;对蛋白酶、氯仿敏感;对紫外线部分敏感。该菌株表现出较好的微生物杀菌剂开发前景。

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.