拮抗细菌Bs-0728对板蓝根根腐病的防治作用

［目的］ 筛选对板蓝根根腐病有较强拮抗作用的生防菌株。［方法］ 采用平板对峙法对137个板蓝根根际土壤样本中分离到的201株拮抗细菌进行测试。［结果］ 筛选出1个对板蓝根根腐病菌有强烈抑制作用的菌株Bs-0728。结合显微镜观察确定Bs-0728菌株对板蓝根根腐病的主要致病菌茄腐镰刀菌（Fusarium solani）菌丝生长有较强的抑制作用，导致菌丝生长畸形，弯曲，部分细胞膨大。田间试验结果表明，Bs-0728的发酵液田间防效达72.97%，且增产86.26%。经形态观察、生理生化反应及16S rDNA 序列分析，初步将此拮抗细菌鉴定为枯草芽胞杆菌Bacillus subtilis。［结论］ 枯草芽孢杆菌Bs-0728菌株是一株很有应用前景的生防菌株。

Biocontrol of Isatis indigotica root rot by the bacterial strain Bs-0728

［Objective］ To screen effective antagonistic bacterium to Isatis indigotica root rot. ［Method］ Dural culture was conducted to test the antagonism of 201 bacterial strains isolated from 137 I. indigotica rhizosphere soil samples. ［Result］ The bacterial strain Bs 0728 showed the highest antagonistic effect against the major Isatis root rot pathogen Fusarium solani. Bs 0728 was highly inhibitory to F. solani by making the mycelia swollen and curly. Treated with fermentation broth of Bs 0728 in field trials, the disease control efficacy reached 72.97%, and the yield of I. indigotica root increased by 86.26% compared with the untreated control. Identification by morphological observations, physiological and biochemical determination, and 16S rDNA sequence analysis showed that the strain belonged to Bacillus subtilis. ［Conclusion］ The stain Bs 0728 is a promising biological strain for application.