拮抗细菌Bs-0728对板蓝根根腐病的防治作用

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

[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。

[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 1. indigotica rhizosphere soil samples. [Result] The bacterial strain Bs-0728 showed the highest antagonistic effect against the major lsatis root rot pathogen Fusariurn 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.