一株人参内生产吲哚乙酸细菌的筛选及鉴定

研究以人参内生细菌为实验对象,采用Salkowski法筛选具有产吲哚乙酸(IAA)能力的菌株,同时采用Ashby培养基验证其固氮潜能,菌碟法及钼锑抗比色法测定其解磷能力,硅酸盐培养基初筛和火焰分光光度法复筛测定解钾能力,刃天青方法检测产生铁载体能力,α-酮丁酸法测定ACC脱氨酶活性;沙土法测定活性菌株对种子发芽的影响.结果从118株菌株中得到1株具有较高产IAA的菌株JJ5-2,其产IAA能力为10.2 mg·L^-1;且具有解磷、解钾、固氮和产生铁载体特性;能显著促进人参种子根的生长;通过形态学、生理生化及16S rRNA基因序列分析鉴定菌株JJ5-2为苏云金芽孢杆菌Bacillus thuringiensis.

Screening and identification of indoleacetic acid producing endophytic bacterium in Panax ginseng

Endophytic bacteria which was producing indoleacetic acid was screened from Panax ginseng by using the Salkowski method.The active strain was also tested for its ability of nitrogen fixation by using the Ashby agar plates, the PKV plates and quantitative analysis of Mo-Sb-Ascrobiology acid colorimetry was used to measure its ability of phosphate solubilization, for its ability of potassium solubilization the silicate medium and flame spectrophotometry was used, for its ability of producing siderophores the method detecting CAS was used, for its ability of producing ACC deaminase the Alpha ketone butyric acid method was applied.And the effect on promoting growth of seed by active strain was tested.The results showed that the indoleacetic acid producing strain of JJ5-2 was obtained from 118 endophytes, which the content of indoleacetic acid was 10.2 mg·L^-1.The JJ5-2 strain also had characteristics of phosphate and potassium solubilization, nitrogen fixation, producing siderophores traits, and the promoting germination of ginseng seeds.The JJ5-2 strain was identified as Bacillus thuringiensis by analyzing morphology, physiological and biochemical properties and 16S rRNA gene sequences.