中文摘要：

生防菌Bs-916对水稻纹枯病具有很好的防治效果,分泌的脂肽类化合物bacillomycin L是其抗真菌活性的关键因子之一。Bacillomycin L抑菌活性的定性及定量分析结果表明：其对常见的12种病原真菌的菌丝生长均有抑制作用,但其对不同病原真菌的毒力存在显著差异。Bacillomycin L对番茄灰霉Botrytis cinerea和稻瘟病菌Magnaporthe oryzae的毒力最强,抑制中浓度（IC50）分别为0.28μg.mL-1和0.35μg.mL-1;对大多数病原真菌IC50在1～3μg.mL-1;对水稻恶苗病菌Fusarium fujikuroi和串珠镰刀菌F.moniliforme毒力最差,IC50分别为28.99μg.mL-1和45.92μg.mL-1。显微观察表明bacillomycin L能致畸病原真菌菌丝和抑制孢子萌发。Bacillomycin L对稻瘟病和水稻纹枯病都有一定的防治效果,当使用浓度为500μg.mL-1时,对水稻纹枯病和苗瘟的防效分别为70.8%和56.3%。研究结果表明,bacillomycin L具有广谱高效的抗真菌活性,具有开发为环境友好型生物农药的潜力。

英文摘要：

Bacillus subtilis Bs916 is an effective biocontrol agent against rice sheath blight caused by Rhizoctonia solani.The lipopeptide bacillomycin L plays a crucial role in biocontrol activities of strain Bs-916.In this study,bcillomycin L was isolated and purified from the culture of B.subtilis Bs-916 and in vitro assay indicated that bacillomycin L was toxic to all the 12 tested pathogenic fungi and IC50 values varied from 0.2 μg·mL-1 to 40 μg·mL-1.Magnaporthe oryzae and Botrytis cinerea showed the highest sensitivity to bacillomycin L and IC50 values on hyphal growth were 0.35 μg·mL-1 and 0.28 μg·mL-1,respectively. For most of the tested fungi,IC50 values were 1-3μg·mL-1.Fusarium fujikuroi and F.moniliforme showed the lowest sensitivity to bacillomycin L and IC50 values were 28.99 μg·mL-1 and 45.92 μg·mL-1,respectively.Microscopic observation demonstrated that the hyphae of the pathogenic fungi treated with bacillomycin L showed abnormal growth,and conidia produced enlarged and constricted germ tube.Cellular leakage was also observed when bacillomycin L was used in high concentration.With 500 μg·mL-1 bacillomycin L,the control efficiency against rice sheath blight and rice seedling blast reached 70.8% and 56.3%,respectively.Results above indicated that bacillomycin L has a broad antifungal activity and potential application in biological control.