Microbial ecological study about the root zone soil of the healthy and diseased celery plant in Inner Mongolia | 内蒙古芹菜根腐病病株和健株根域土壤的微生物生态研究

chinois. 探讨内蒙古芹菜根腐病发生的微生物生态机制，为利用微生态调控技术防治蔬菜根腐病提供科学依据。采用稀释平板法，以内蒙古根腐病芹菜病株和健株的根区土壤、根表土壤和根系为研究对象，研究了根域微生物数量及其组成；同时利用CTAB法对优势真菌的组成进行了分析，并进行了分子生物学鉴定。（1）就根区土壤而言，发病初期病株细菌和真菌的数量分别较健株有所减少，而在发病中、晚期，病株细菌和真菌数量均较健株有所增加。（2）就根表土壤而言，发病初期病株细菌数量较健株减少，发病中期和晚期的细菌数量均较健株大幅提高；发病初、中和晚期根表土壤的真菌数量均高于健株。（3）发病初、中和晚期，根区和根表土壤中的细菌/真菌（B/F）值均大幅度减小，表明病原真菌所占比例大幅度提高，土壤由细菌型向真菌型转变。（4）分子生物学鉴定表明，优势病原真菌分别为接骨木镰刀菌（Fusarium sambucinum）、链格孢菌（Alternaria alternate）和尖孢镰刀菌芬芳变种（Fusarium oxysporum var. redolens），这3种病原真菌在根区、根表土壤及根内的数量远远高于常见真菌。内蒙芹菜根腐病的发生与根区、根表土壤中的微生物区系异常变化及3种病原真菌数量的大幅度增加密切相关。

anglais. To explore the celery disease of root rot happened in the Inner Mongolia, we tried to find the reasons for microbial ecology. The root-zone soil, root-surface soil and the root of the healthy and diseased plant are studied by the method of “dilution-plate” to understand the root-zone microorganism quantity and composition. The molecular-biology identification of the dominant fungi by the CTAB method is also done in this study. (1) In rhizosphere soil, the number of bacteria and fungi of diseased plant in initial stage is less than that of healthy plant, but the number of bacteria and fungi in midterm and late stage of the diseased plant-increases respectively compared with the healthy plant. (2) In root-surface soil: the number of bacteria of diseased plant in initial stage is less than that of healthy plant, but the number of bacteria in midterm and late stage of the diseased plant increases. The number of fungi in the root-surface of diseased plant in initial stage, midterm and late stages respectively increases compared with the healthy plant. (3) In initial stage, midterm and late stages, the ratio of B/F significantly reduces in rhizosphere soil and root-surface soil, which indicates that the proportion of pathogenic fungi increases and soil form bacteria type to fungi type. (4) The molecular-biology identification: the superiority epiphyte is the Fusarium sambucinum, Alternaria alternate, Fusarium oxysporum var. redolens. Also the three kinds of pathogenic fungi in the root zone, root surface soil and roots are much higher than the normal fungi. The occurrence of celery rot root disease is closely related to the differences of the surface and zone soil microbial flora in Inner Mongolia. The occurrence of celery rot root disease is related to three kinds of pathogenic fungi.