向日葵枯萎病拮抗芽胞杆菌的筛选与生防评价

目的筛选向日葵枯萎病拮抗芽胞杆菌菌株并研究其抗菌谱,探讨环境条件对菌株抑菌活性的影响并通过植物栽培完成生防评价。方法从向日葵根际土壤中选择性分离芽胞杆菌,通过5点对峙法确定1株高效拮抗菌株,进行鉴定后,测定其抑菌谱;单因素实验探讨环境条件对抑菌活性的影响;向日葵发芽实验完成生防评价。结果确定1株高效的枯萎病拮抗菌株WBFL-1,经鉴定为枯草芽胞杆菌,该菌对镰刀菌属具有广谱抗性,其抑菌活性的最佳条件是温度40℃,pH值7.0,接种量150μL,发酵时间48 h。生防评价表明该菌对枯萎病的拮抗效果显著。结论该菌可为农作物枯萎病的生物防治提供有效菌种储备。

Screening and biocontrol evaluation on Bacillus spp antagonistic to sunflower Fusarium wilt

Objective To screen Bacillus strains antagonistic to sunflower Fusarium wilt, study their antimicrobial spectrum, explore the effects of environmental conditions on their antimicrobial activity and perform biocontrol evaluation. Methods The Bacillus spp strains were selectively isolated from the rhizosphere soil of sunflower. A highly effective antagonistic strain was identified using 5-point confrontation method, and its bacteriostatic spectrum was determined. The effect of environmental conditions on the bacteriostatic activity was explored through single factor experiment. The biocontrol evaluation was completed through sunflower germination experiment. Results An efficient antagonistic strain WBFL-1 against Fusarium wilt was identified as Bacillus subtilis. The strain had broad-spectrum resistance to Fusarium. The optimum conditions for its bacteriostatic activity were temperature of 40 ℃, pH of 7.0, inoculation volume of 150 μL and fermentation time of 48 hours. Biological control evaluation showed that the strain had significant antagonistic effect against Fusarium wilt. Conclusion The strain can provide an effective reserve for biological control of crop Fusarium wilt.