【摘要】 以致病力存在分化的香蕉枯萎病病原菌(Fusarium oxysporum f.sp.cubense)菌株群为靶标,从发病香蕉园香蕉根际土壤中分离获得一株芽胞杆菌R21g9,平板抑菌能力测定结果显示,R21g9不仅对香蕉枯萎病菌的不同菌株具有较强的抑制能力,还对西瓜枯萎病病原菌(F.oxysporum f.sp.niveum)、芒果蒂腐病病原菌(Botryodiplodia theobromae Pat)和新月弯孢霉(Curvularialunata)等植物病原真菌有较强的抑制作用。利用生理生化和分子生物学方法对该菌开展鉴定研究,API系统将该菌鉴定为地衣芽胞杆菌(Bacillus licheniformis);利用16S rDNA序列开展的系统发育分析仅能确定该菌为枯草芽胞杆菌组成员,不能鉴定到种;利用gyrB基因序列开展的系统发育分析将R21g9鉴定为解淀粉芽胞杆菌(Bacillus amyloliquefaciens)。拮抗机制研究结果显示,R21g9对真菌的作用方式为抑菌,抑菌物质存在于发酵上清中,可以被10%~90%的硫酸铵沉淀。对硫酸铵沉淀的粗提物进行抑菌活性检测发现40%、50%、60%、70%和80%饱和度硫酸铵沉淀物具有强的抗菌活性,主要拮抗物质可以被50%饱和度硫酸铵盐沉淀,此沉淀物的抑菌率最高,可以达到95.65%。更多还原

【Abstract】 An antifungal Bacillus R21g9 was isolated from the soil in banana garden according to its inhibition on a group of Fusarium oxysporum f.sp.cubense strains which showed pathogenic differentiation.This strain also showed high inhibitive effects on F.oxysporum f.sp.niveum,Botryodiplodia theobromae Pat and Curvularia lunata.Based on the results of Physiological-biochemistrical and molecular biological identification,it was identified as Bacillus licheniformis by API and was identified as Bacillus subtilis group species by the phylogenetic analysis of 16S rDNA,Finally,it was identified as Bacilus amyloliquefaciens based on the phylogenetic analysis of gyrB gene sequence.Antagonistic mechanism studies showed R21g9 didn’t kill the cells,but inhibited the growth of the fungal hypha.The antifungal material existed in the cell free culture supernatant and could be precipitated by different concentration of ammonium sulfate from 10% to 90%.The components precipitated by 40%~80% of ammonium sulfate had high antifungal activities,especially that precipitated by 50% of ammonium sulfate,its inhibition rate was the highest,which was up to 95.65%.更多还原