芽孢杆菌BJ-6的抗菌物质及其抑菌作用

芽孢杆菌(Bacillussp.)BJ-6菌株分离自北京市门头沟区杏树根际土壤,室内抑菌测定发现BJ-6菌株对苹果轮纹病(Physalospora piricola)、苹果斑点落叶病(Alternaria mali)和苹果树皮腐烂病(Valsa mali)、白菜黑斑病(A.brassicae)、番茄灰霉病(Botrytis cinerea)、茄子黄萎病(Verticillium dahliae)的病原菌均有较强的抑菌作用。对其代谢产生的抗菌物质的稳定性测定表明:抗菌物质在偏酸性和中性条件下能够耐受121℃高温处理20 min;但在偏碱性条件下不具备热稳定性,热处理后失去原来的抑菌活性。采用硫酸铵分级沉淀得到抗菌粗蛋白,其中饱和度在30%~40%之间沉淀的蛋白抗菌活性最强。紫外吸收测定显示只有具有274 nm附近吸收峰的蛋白液有抑菌活性,且抗菌粗蛋白可引起白菜黑斑病菌菌丝畸形。

Antifungal Substance from Bacillus sp. BJ-6 and Its Antagonism against Plant Pathogens

The strain BJ-6 of Bacillus sp.was isolated from the rhizosphere of apricot trees in Mentougou,Beijing,China,and showed strong antifungal activity to six tested species of plant pathogens,i.e.Physalospora piricola,Alternaria mali,Valsa mali,A.brassicae,Botrytis cinerea and Verticillium dahliae.This study showed that the culture liquid of BJ-6 strain preserved its inhibitory activity to tested pathogenic fungi when autoclaved at 121℃ for 20 min at pH≤7.0,and was not stable when treated at the same temperature at pH≥9.0.The crude antifungal proteins were separated from BJ-6 fermented solution by ammonium sulphate precipitation at different saturations from 20% to 90%,among which the crude antagonistic proteins precipitated by a saturation of 30%~40% had the highest inhibiting activity.The crude proteins solution which had an UV absorption peak at 274 nm had inhibiting activity against plant pathogenic fungi and brought the A.brassicae hyphae abnormal.