枯草芽孢杆菌生防菌株SEM-9根际定植及对根际土壤微生物多样性的影响

Rhizosphere colonization of Bacillus subtilis biocontrol strain SEM-9 and the effect on microbial diversity in rhizosphere soil

【目的】研究枯草芽孢杆菌生防菌株SEM-9在作物根际的定植规律及对根际土壤微生物多样性的影响。【方法】通过自然转化法对SEM-9菌株进行绿色荧光蛋白标记,利用倒置荧光显微镜观察该菌株在作物根际土壤、根表面及根系内组织的定植情况;并以土传病害土壤为试验对象,通过高通量测序初步分析SEM-9菌株处理后根际土壤中微生物多样性的变化。【结果】构建了稳定表达绿色荧光蛋白的重组菌株SEM-9-pGFP_(22)。荧光显微镜观察结果表明,SEM-9-pGFP_(22)重组菌株可以在根际土壤和根表面定植,但是无法在根内组织或细胞内定植。SEM-9菌液处理显著降低了黄瓜土传病害的发病率,提高了根际土壤真菌微生物的多样性。【结论】成功建立了SEM-9菌株的GFP标记方法,明确了该菌株的根际定植规律及对黄瓜土传病害的防治效果,为后期开发替代型微生物肥料奠定了基础。

【Objective】In order to study the colonization rule of Bacillus subtilis biocontrol strain SEM-9 in the rhizosphere of crops and its influence on the microbial diversity of rhizosphere soil.【Method】The strain SEM-9 was labeled with green fluorescent protein by natural transformation method,and the colonization in rhizosphere soil,on root surface and in root tissue were observed by inverted fluorescence microscope.The changes of microbial diversity in rhizosphere soil treated with the strain SEM-9 were analyzed by high-throughput sequencing using soil with soilborne diseases as test material.【Result】The recombinant strain SEM-9-pGFP_(22) stably expressing green fluorescent protein was constructed.The observations of fluorescence microscopy showed that SEM-9-pGFP_(22) could colonize on the rhizosphere soil and root surface,but not in root tissue or cell.After treated with the SEM-9 suspension,the incidence rate of cucumber soilborne disease significantly reduced,and the fungal diversity in rhizosphere soil increased.【Conclusion】The GFP labeling method of SEM-9 strain was successfully established,and the rhizosphere colonization rule of the strain and the control effect on cucumber soilborne diseases were clarified,which lays a foundation for the later development of alternative microbial fertilizer.