一株花生根际铁载体产生菌的分离鉴定及耐药性分析

Isolation,Identification and Resistant Features of a Siderophores Producting Bacteria from Peanut Rhizosphere

目的:从花生根际筛选铁载体产生能力较强的菌株,对其进行鉴定及耐药性分析。方法:用梯度稀释法从花生根际中分离出细菌,在刃天青(CAS)检测平板上依显色圈的大小从中筛选出一株铁载体产生能力较强的菌,并对其进行生理生化鉴定和16S rDNA序列分析,用抗生素梯度平板检测其对9种常见抗生素的抗性。结果:筛选出一株产铁载体的菌株D15,13项生理生化指标除甲基红试验呈阳性外,其他均与恶臭假单胞菌相同;其16S rDNA与恶臭假单胞菌的同源性为100%;该菌对氨苄青霉素、氯霉素、利福平、红霉素、新霉素、链霉素、四环素都有不同程度的的抗性,对卡那霉素和庆大霉素表现较强的敏感性。结论:获得铁载体产生菌D15,经鉴定为恶臭假单胞菌,该菌耐药性符合用转座子诱变法研究铁载体合成的相关基因的条件。

Objective： To isolate and identify a siderophores producing bacterium from the peanut rhizosphere. Methods： Strains were isolated from peanut rhizosphere by gradient dilution, and then siderophores producing bacterium was screened out based on the chrome azurol S （CAS） assay. This strain was identified based on the characteristics of morphological, cultivation, physiology, and the 16S rDNA sequence; 9 familiar antibiotics were examined by using antibiotic gradient plates. Results： A siderophores producing bacterium D15 was screened out and 13 physiological and biochemical features were done. All except the M.R assay was according with Pseudomonas putida. Its 16S rDNA sequence was identical to that of P.putida at 100% level. The strain can sustain ampicillin, chloramphenicol, rifampin, erythromycin, neomycin, streptomycin, tetracyclin in different concentrations and showed high sensitive to kanamycin and gentamycin. Conclusion： A siderophores producing bacterium D15 was obtained, which was identified as P.putida. The resistant features of this strain can be used for research genes involved in siderophores synthesize by transposon mutagenesis.