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为探讨银杏内生细菌对萝卜软腐病的防病作用,通过块根接种和温室盆栽试验筛选对萝卜软腐菌Pectobacterium carotovorum subsp.carotovorum具有高效抑制作用的生防菌株,共获得8株拮抗作用较强的内生细菌,其中菌株Hy11抑菌作用明显。对生防菌株Hy11进行了形态观察、生理生化特性测定、16S rDNA和gyrB基因序列分析,并应用绿色荧光蛋白基因标记菌株Hy11,研究该菌株在萝卜体内的定殖动态。结果显示,该菌株对萝卜软腐病具有较好的防效,对萝卜块根和幼苗的防治效果分别为77.9%和66.7%;对萝卜幼苗的促生率达113.28%。经鉴定,菌株Hy11为解淀粉芽胞杆菌Bacillus amyloliquefaciens。标记菌株Hy11-gfp在喷雾接种银杏叶片后0～3 d种群数量呈急剧下降趋势,10 d后保持相对稳定;其在萝卜的根、茎和叶中均能够定殖,在根中的定殖数量最高可达1.2×104CFU/g。
In order to explore the preventive effect of ginkgo endophytic bacteria on soft rot of radish, eight antagonistic effects were obtained by screening tubers and greenhouse pot experiments with biocontrol strains with high inhibitory effect on Pectobacterium carotovorum subsp. Carotovorum Strong endophytic bacteria, of which strain Hy11 obvious antibacterial effect. The biocontrol strain Hy11 was subjected to morphological observation, physiological and biochemical characteristics analysis, 16S rDNA and gyrB gene sequence analysis, and the green fluorescent protein gene marker strain Hy11 was used to study its colonization dynamics in radish. The results showed that the strain had a good control effect on soft rot of radish, the control effect on root and seedlings of radish was 77.9% and 66.7% respectively, and the productivity of radish seedlings reached 113.28%. It was identified that strain Hy11 is Bacillus amyloliquefaciens. The population of marker strain Hy11-gfp declined rapidly from 0 to 3 days after spray inoculation with Ginkgo biloba leaves, and remained relatively stable after 10 days. It was colonized in roots, stems and leaves of radish and colonized in roots The maximum amount of up to 1.2 × 104CFU / g.