枯草芽孢杆菌Bs-916的抑菌活性及其抑菌物质初探

为了揭示从土壤中分离出的拮抗菌—枯草芽孢杆菌Bs-916的抑菌作用和抑菌机理,采用管蝶法、平板涂抹法及孢子盟发法测定了Bs-916及其代谢液对水稻纹枯病菌、蚕豆枯萎病菌等8种病原菌的抑菌活性,结果表明其对供试的大多数病原菌均具有较强的抑菌活性,如Bs-916及其代谢液对水稻纹枯病菌的抑制率分别为95.4％和70.7％,对水稻稻曲病菌的抑制率均为100%。为了探索Bs-916胞外物质的种类及特性,分别采用丙酮沉淀、PEG沉淀、等电点沉淀和超微浓缩等方法从Bs-916代谢液中获得了沉淀物或截留物,它们均具有抑菌活性。沉淀物经蛋白酶K 处理后,活性减弱,说明Bs-916胞外抗菌物质具有蛋白质的性质。

Analysis on the Antifungal Activity of Bacillus subtilis Strain Bs-916 and Its Extract

Bacillus subtilis strain Bs-916 which was isolated from rice field soil was used in controlling rice shealth blight and rice false smut.Bs-916 and its extract exhibited high antifungal (antibacterial) activity toward Rhizoctonia solani,Fusarium moniliforme,Fusarium oxysporum,Picularia grisea,Ustilaginoidea virens,Xanthomonas campestris pv.oryzae and Xanthomonas campestris pv.oryzicola.Inhibition rate of Bs-916 and its extract were 95.4% and 70.7% toward R.solani,100% and 100% toward U.virens,respectively.The extract of Bs-916 was deposited by acetone,PEG6000,ammonium sulfate and different pH value,the extract were also drawn by Ultra-4 centrifugal devices,and the above distilled substances showed high antifungal activity toward Rhizoctonia solani.The antifungal activity of the extract was decreased when it was treated with protease K.The results implied that an antifungal protein existed in the extract of Bs-916.