黄芪根腐病生防菌株的筛选鉴定及其防效评价

以沙棘根瘤内生细菌为材料，筛选对黄芪根腐病具有生防效果的菌株，以期为黄芪根腐病的生物防治提供优质菌种。采用平板对峙法，筛选得到抑菌性能较强的沙棘根瘤内生细菌TT14，并检测其对4株黄芪根腐病原菌的抑菌活性；根据形态和培养特征，生理生化特性及16S rRNA基因序列分析，对菌株TT14进行鉴定；通过盆栽试验，测定菌株TT14发酵液对黄芪根腐病的防治效果。结果显示，25株沙棘根瘤内生细菌中，11株具有抑制黄芪根腐病的能力，其中5株对供试的4株黄芪根腐病病原菌都表现出较好的抑菌效果，在这5株内生菌中TT14抑菌效果最佳，其对4株病原菌的抑菌率均在54.52%以上；经鉴定菌株TT14为特基拉芽孢杆菌(Bacillus tequilensis)；盆栽试验显示菌株TT14发酵液对黄芪根腐病有明显的生防效果，其防治效果达65.68%，较对照组提高38.08%。综上可见，沙棘根瘤内生细菌TT14具有较强的抑制黄芪根腐病的活性，并具有较好的生防效果。

Screening, Identification, and Biocontrol Effect of Antagonistic Bacteria against Astragalus membranaceus Root Rot

The seabuckthorn nodules was taken as experimental material, the antagonistic endophytic bacteria against A.membranaceus root rot disease were isolated.It was expetcted to provide good strains for biologically controlling A.membranaceus root rot. More specifically, the strain TT14 showing good antagonistic activity on A.membranaceus root rot was selected by plate confrontation method, and the inhibition activities of the strain against four pathogens of root rot of A.membranaceus were surveyed for further study. The strain TT14 was characterized by morphological, cultural, physiological, biochemical tests and 16S rRNA phylogenetic analysis. A pot experiment was conducted to evaluate the control effect of the fermentation broth of TT14 against root rot of A.membranaceus.The further data showed that Elevenendophytic strains isolated from seabuckthorn nodules had the antagonistic activity against A.membranaceusroot rot pathogens, five strains displayed strong antagonistic effects against tested pathogens. The strain TT14 displayed a highest bacteriostatic rate of 54.52% compared with tested pathogens among all tested bacteria,and was identified as Bacillus tequilensis. Moreover, the pot experiment showed that the fermentation broth of TT14 had an inhibitory effect of 65.68% against root rot disease of A.membranaceus, which showed a significant difference compared with the control treatment. Taken all results together, the endophyte TT14 isolated from seabuckthorn nodules has the potential to be developed as a good biological agent to control root rot disease of A.membranaceus.