烟草黑胫病拮抗根际芽胞杆菌FB-16的筛选鉴定及其抑菌活性

为获得对烟草黑胫病有较强生防效果的拮抗细菌,从健康烟草根际采集30份土壤样品,分离纯化得到347株细菌,经病原真菌定向筛选后得到1株对烟草黑胫病菌等病原真菌拮抗活性较好的细菌FB-16,其对烟草黑胫病菌的抑菌带宽为23mm。采用菌丝生长速率法、作用机制试验、温室防病试验测定FB-16的抑菌作用,并通过形态学特征、生理生化特征及16S rDNA序列分析对菌株进行鉴定。结果显示,菌株FB-16发酵液对烟草黑胫病菌菌丝生长抑制率为95.96%;其代谢产物对烟草黑胫病菌菌丝有致畸作用;菌株FB-16为解淀粉芽胞杆菌Bacillus amyloliauefaciens(Gen-Bank登录号为JN245982);饱和度25%硫酸铵获得的抑菌物质对烟草黑胫病菌的抑菌活性较高,抑菌圈直径达42.00 mm;FB-16活性产物处理的烟草植株在接种烟草黑胫病菌7天后的防治效果为69.96%。表明菌株FB-16在烟草黑胫病生物防治中具有潜在的利用价值。

Screening, identification and antifungal activity of antagonistic rhizospheric Bacillus FB-16 against tobacco black shank

In order to get a strong effect biocontrol bacteria for tobacco black shank, 347 bacteria strains were isolated from 30 soil samples, which collected from healthy tobacco rhizospheric soil. FB-16, a strain with strong effect on Phytophthora nicotianae, its inhibition zone was up to 23 mm. The methods of inhibition rate of mycelium growth, antifungal mechanism experiment, bonsai experiment in greenhouse were used to determine its antifungal effect. This strain was identified based on morphological, physiological and biochemical characteristics, and 16S rDNA phylogenetic analysis. The results showed that the inhibition rate of FB-16 fermented liquid against the mycelium growth of P.nicotianae was 95.96%. The FB-16 metabolite showed teratogenic effects on mycelia of P.nicotianae. The strain FB-16 was identified as Bacillus amyloliauefaciens (GenBank accession JN245982). The antifungal metabolite from stain FB- 16 extracted by 25% ammonium sulfate showed the most effective inhibition toward P.nicotianae, and its inhibition zone diameter was up to 42.00 mm. In the 7th day after treated with FB-16, the control effect on tobacco reached 69.96%. Conclusively, it has potential value in biological control against tobacco black shank.