枯草芽孢杆菌YA-3对番茄早疫病的防治作用

Control efficacy of Bacillus subtilis YA-3 on tomato early blight

从西洋参种植土壤中分离获得一株具有抗真菌活性的细菌YA-3,杯碟法测定表明,该拮抗菌对13种植物病原真菌均有不同程度的抑制作用,其中对番茄早疫病抑制率达82.2%;YA-3培养滤液可导致番茄早疫病病原菌菌丝畸变、枯萎或者断裂,阻碍菌丝生长,并能够抑制其孢子萌发,抑制率达92.3%以上;利福平抗性标记试验表明,YA-3在番茄叶片上有很强的定殖能力,第26 d仍能检测到该菌;经盆栽试验结果表明,YA-3发酵液可使番茄叶片发病率显著降低,防治效果可达到75.52%;根据其形态、生理生化特性及16S r DNA同源性分析结果,鉴定为枯草芽孢杆菌(Bacillus subtilis)。

Biocontrol bacterial YA-3 was isolated from the soil of American ginseng planting in Shaanxi Liuba. The results of the antagonistic tests by cylinder plate methods showed that there were 13 kinds of plant patho- gens inhibited in different degrees by fermentaion broth of the antagonistic bacteria, the inhibited rate of toma- to early blight reached 82.2%. The culture filtrate of YA-3 can lead to the pathogen hyphae of tomato early blight distortion, wither or fracture and inhibit the growth of mycelia. Additionally, the inhibition rate of the spore germination was more than 92.3 %. Determining of the colonization by the signed rifampicin-resistance in YA-3 showed that it could colonize well in tomato leaves, the group which sprayed the fermentation broth of YA-3 firstly was found to have the longest colonization time and the existence of antagonistic bacteria can still be detected within 26 days. The pot experiment revealed that the control effect reached 62.43%. It was identi- fied as Bacillus subtilis on the basis of morphological, physiological and biochemical characters as well as the sequence analysis of 16S rDNA.