抗不同生化型青枯菌的生防菌筛选鉴定及其活性分析

为更好地利用生防菌控制青枯病危害,从不同地区的土壤中分离到569株细菌菌株,筛选到3株对5种不同生化型青枯劳尔氏菌Ralstonia solanacearum具有较强拮抗活性的菌株,其中菌株BS2004的拮抗活性最强。以BS2004的菌悬液为对照,分别测定无菌滤液、蛋白酶K及高温热处理后拮抗物质抑菌活性的变化。结果显示,蛋白酶K及高温热处理后,该菌的抑菌活性显著降低,表明其主要抑菌成分为蛋白类物质。在设施栽培条件下用生防菌BS2004菌悬液处理番茄植株,能有效控制番茄青枯病的发生,防治效果达66.75%,同时还发现,重新分离得到的青枯菌菌体数明显受到生防菌的抑制。通过对BS2004的形态、生理生化特征、脂肪酸鉴定、16S rDNA序列等进行分析,该菌株被鉴定为解淀粉芽孢杆菌Bacillus amyloliquefaciens。

Evaluation and identification of antagonistic bacteria against different biovars of Ralstonia solanacearum and their active metabolites

It is necessary to use biological control agents rightly for control plant bacterial wilt effectively. Three bacterial strains with high antagonistic activity against 5 different biovars of Ralstonia solanacearum were screened out of 569 bacterial strains from the soil of different regions, and strain BS2004 showed the strongest inhibitory effect. Antagonistic activity of strain BS2004 were conducted under the condition of bacterial suspension, bacteria-free filtrate, bacterial suspension treated with proteinase K and heat sterilization. The result showed that after proteinase K and heat treatments, bacteriostatic activity of strain BS2004 decreased significantly which indicated proteins as the main antibacterial substance. Application of BS2004 suspension on tomato plants reduced the disease incidence of tomato bacterial wilt, and the control efficiency was 66.75%. The population density of R.solanacearum in the soil indicated that the pathogen populations were significantly inhibited by strain BS2004. This bacterium was identified as Bacillus amyloliquefaciens using the colony morphology, physiological and biochemical characteristics, fatty acid methyl esters analysis and 16S rDNA sequencing.