解淀粉芽孢杆菌FS6在人参体内的定殖特性及对人参诱导抗病性

Colonization and induced resistance of Bacillus amyloliquefaciens FS6 in ginseng

【目的】明确解淀粉芽孢杆菌(Bacillus amyloliquefaciens)FS6在人参体内的定殖规律及其在病原菌胁迫下对人参防御酶活性的影响,为揭示FS6诱导人参产生抗病性的诱导抗病机制奠定基础,进而为人参根部病害的绿色防控提供依据。【方法】采用抗生素标记法获得FS6菌株抗利福平的突变体菌株,采用灌根和叶面喷雾两种方法接种,研究FS6在人参植株体内及人参根际土壤中的定殖规律;采用灌根法,利用盆栽试验研究不同处理条件下FS6对人参抗病相关防御酶活性的影响。【结果】从含300μg/mL利福平抗性平板上得到标记菌株,该标记菌株能在NA培养基上稳定生长,抗性丢失率为0,且标记菌株与野生菌株的拮抗能力无明显差异。定殖试验结果表明,灌根和叶面喷雾两种接种方式下,FS6Rif菌株均能在人参植株各个部位及根际土壤中定殖,并能在人参体内转移。其中,灌根后FS6Rif在土壤中的定殖量在处理后第1天达到最大值,为4.8×103 CFU/g;叶面喷雾后FS6Rif在叶片中的定殖量在处理后第1天达到最大值,为3.2×103 CFU/g。FS6发酵液处理后再接种人参根腐病菌,与其他3个处理相比,人参防御酶活性显著提高,CAT、POD和PPO分别在FS6发酵液灌根处理后第12,15和18天达到峰值。【结论】FS6菌株能够在人参植株体内稳定定殖并传导,且能在一定程度上诱导人参产生抗病性。

【Objective】This study investigated the colonization and effects of Bacillus amyloliquefaciens FS6 on ginseng defense enzyme activities under pathogen stress to provide evidence for the further understanding induced resistance and green control of ginseng root disease.【Method】Mutant strains of FS6 resistant to rifampin were screened and obtained using the antibiotic label method.The colonization of FS6 in ginseng was determined by the root irrigation and spraying methods.The effect of FS6 on activities of three defense enzymes of ginseng was then determined by pot experiment.【Result】The marked strain was obtained from the resistant plating medium with rifampin of 300μg/mL.The strain could grow steadily on the NA medium with the resistance loss rate of 0.The antagonism abilities of the marked strain had no significant difference from the wild strains.The colonization trials showed that the labeled strains of FS6Rif could efficiently colonize and transmit in ginseng and soil with two inoculation methods.The maximum density in soil was 4.8×103 CFU/g 1 d after root irrigation,and the maximum density in leaf was 3.2×103 CFU/g 1 d after spraying.Defense enzyme activity assay test showed that the activities of polyphenol oxide(PPO),peroxidase(POD)and catalase(CAT)in ginseng leaves were significantly increased after inoculation with Fusarium solani and FS6,and the peak values appeared at 12,15 and 18 d after root irrigation,respectively.【Conclusion】Bacillus amyloliquefaciens FS6 could efficiently colonize and transmit in ginseng and could induce disease resistance of ginseng.