利用aiiA基因筛选抗烟草青枯病生防菌株及其鉴定

Screening of Biocontrol Bacteria Against Ralstonia pseudosolanacearum With Gene aiiA and Identification of the Bacteria

为了有效筛选出对作物青枯病具有防治效果的生防细菌,本研究采用群体感应淬灭基因aiiA的简并引物进行PCR扩增与室内盆栽防治效果测定相结合的方法进行生防细菌的筛选,并通过传统的细菌学鉴定方法和分子生物学手段明确其分类地位。结果表明,从253株生防菌株中获得了12株含有aiiA基因的生防菌株;进一步盆钵防效测定,获得了一株对烟草青枯病具有较好防治效果的生防菌株B15。该菌株接种处理后,烟草青枯病可推迟2 d发生,在接种处理14 d后其对烟草青枯病防治效果为68.33%。B15菌株在NA平板培养基上菌落呈圆形、白色、表面有光泽且粗糙,菌体杆状,革兰氏染色阳性,耐盐性为7%;生理生化测定、16S rDNA和gyrB基因序列分析表明,菌株B15为蜡样芽胞杆菌(Bacillus cereus)。本研究获得的含有群体感应淬灭基因aiiA的蜡样芽胞杆菌B15菌株,为作物青枯病生物防治提供了新的生防菌株资源。

In order to effectively screen the biocontrol bacteria that had a good control effect to bacterial wilt disease(Ralstonia pseudosolanacearum), in this paper, quorum-sensing quenching gene aiiA was amplifed and control effects in greenhouse were tested. The taxonomic status was clarified by traditional bacteriological and molecular biological identification methods. The results showed that 12 biocontrol strains containing aiiA gene were obtained from 253 test strains, and the strain B15 that had a good control effect to tobacco bacterial wilt was screened out by further control test in greenhouse. The disease occurrence was delayed for 2 days, and the control effect was 68.33% in 14 days after inoculation with strain B15. On NA plate the colony of the strain B15 was round, white, and the surface was shiny and rough. The bacterial cell was rod-shaped and gram-positive. The salinity tolerance of the bacteria was 7%. According to the results of physiological and biochemical assay, 16 S rDNA and gyrB gene sequence analysis, the strain B15 was identified as Bacillus cereus. The strain B15(B. cereus)with quorum quenching-sensing gene aiiA might provide a new biocontrol bacterial strain against R. pseudosolanacearum.