A high efficient antifungal strain Bacillus subtilis QM3 from Qinghai yak dung was isolated. The antifungal protein produced by QM3 was extracted by 60％ ammonium suffate and SDS-PAGE gel electrophoresis and its stability was investigated by confrontation culture. The results showed the protein presented significant antifungal activity against Alternaria solani and the molecular weight was identified as 47. l×l04. There was no significant difference (P ＞ 0.05) for inhibitory activity among different levels of treatment factors including temperature, pH, ultraviolet radiation and proteinases, which indicated the antifungal protein held a good stability. The research showed a potential application of strain QM3 for the control of fungal diseases.%枯草芽孢杆菌QM3是从青海牦牛粪中分离筛选出的1株对植物病原真菌高效拮抗菌株,为了开发和应用QM3菌株,本研究探讨了QM3抗真菌蛋白的稳定性.采用硫酸铵盐析、SDS-PAGE凝胶电泳从其发酵液中分离抗真菌蛋白,并采用对峙生长法分析了该蛋白的稳定性.结果显示:60%饱和硫酸铵盐析得到的蛋白具有较好的抑菌活性,其分子量约为4.71×104;该抗真菌蛋白经不同温度、pH值、光照及蛋白酶处理后其抑制率均无显著性变化(P>0.05),具有良好的稳定性.这一结果揭示了QM3菌株可产生稳定性较高的抗真菌天然产物,为QM3菌株的生防应用奠定了理论基础.
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