生防菌复配对烟草黑胫病的防治效果研究

为解决单一生防菌防效不稳定问题，通过平板对峙试验、相容试验、盆栽试验从6株生防菌中筛选对烟草疫霉菌（Phytophthora parasitica var. nicotianae）具有较高拮抗活性的复配菌株组合；利用分子生物学方法对各菌株的16S rRNA和gyrA基因进行系统进化分析，鉴定各菌株分类地位；并采用轮换因子法筛选各菌株的最适发酵培养基。结果表明，GY1、GY10和GY12发酵后混合施用对烟草黑胫病的防治效果最好，平板抑菌率达到86.9%，盆栽防效为74.53%，比GY1、GY10、GY12单独处理分别提高15.34%、27.42%和44.94%；分子鉴定表明，3株菌分别为贝莱斯芽孢杆菌（Bacillus velezensis）、解淀粉芽孢杆菌（Bacillus amyloliquefaciens）和枯草芽孢杆菌（Bacillus subtilis）；并筛选得到了GY1、GY10、GY12的最适发酵培养基，发酵24 h后生物量相较于基础培养基分别增加了75.12%，92.31%和194.55%。

Effect of Biocontrol Agents Mixture on Control of Tobacco Black Shank

In order to address the problem of unstable antibacterial activity of single biocontrol bacteria,a composite strains with high antagonistic activity against Phytophthora parasitica var.nicotianae was screened from six biocontrol bacteria by compatible test,antagonist test and pot test.The taxonomic status of each strain was identified with a phylogenetic analysis of the 16S rRNA and gyrA genes of the strains,and then the optimal fermentation medium for each strain was screened with a single factor test.The co-application of GY1,GY10 and GY12 after fermentation showed the best control effect on tobacco black shank,with the plate inhibition rate reached 86.9%and he potted control effect reached 84.21%,which increased by 17.58%,26.74%and 35.9%compared with single strains of GY1,GY10 and GY12,respectively.Molecular identification showed that the three strains were Bacillus velezensis,Bacillus amyloliquefaciens and Bacillus subtilis,respectively.The optimal fermentation mediums of GY1,GY10,and GY12 were screened,where the biomass of GY1,GY10 and GY12 increased by 75.12%,92.31%,and 194.55%,respectively,compared with the basic medium after 24 hours of fermentation.