玉米联合固氮菌Kosakonia radicincitans GXGL-4A的分离鉴定与固氮特性研究

发布时间：2018-06-30 02:22

本文选题：玉米 + 固氮菌　；参考：《微生物学通报》2016年11期

【摘要】：【目的】固氮微生物是生物固氮的主体,其菌种的选育更是生物固氮研究的基础。本实验室分离鉴定出一株新的固氮菌,并对其固氮相关活性进行初步研究。【方法】固氮菌采用Ashby无氮培养基进行分离纯化。通过形态特征分析、生理生化特征分析、16S r RNA基因序列分析和基因组扫描对固氮菌进行鉴定。利用靛酚蓝-分光光度法检测固氮菌的泌铵能力。固氮酶活性的测定使用乙炔还原法。【结果】从玉米根部分离到一株固氮菌株GXGL-4A,菌体短杆状,大小约为1.5μm×0.5μm,单个或常见2个菌体细胞串联在一起,革兰氏染色结果为阴性。16S r RNA基因序列分析结果表明该菌株与Kosakonia oryzae Fo8A1d 16S r RNA基因序列有95%的相似性,结合形态特征、生理生化特征和基因组扫描,将其命名为K.radicincitans GXGL-4A。对其进行固氮基因nif H的检测,经PCR扩增得到预期的296 bp条带;采用靛酚蓝-分光光度法,测得发酵液中铵态氮含量为2.5 mg/L,表明该菌株具有较好的泌铵能力。乙炔还原法测其固氮酶活性,以乙烯生产量表示,结果显示GXGL-4A菌株在无氮培养基上能够有效地还原乙炔,达到232.94 nmol C2H4/(m L·h)。【结论】菌株GXGL-4A是一株可较好地分泌铵的新的固氮菌,具有很好的研究价值。
[Abstract]:[objective] nitrogen fixing microorganism is the main body of biological nitrogen fixation, and the breeding of its strain is the foundation of biological nitrogen fixation research. A new strain of nitrogen-fixing bacteria was isolated and identified in our laboratory, and its nitrogen-fixing related activities were preliminarily studied. [methods] the nitrogen-fixing bacteria were isolated and purified by Ashby nitrogen-free medium. The 16s rRNA gene sequence analysis and genome scanning were used to identify the nitrogen-fixing bacteria by morphological analysis, physiological and biochemical analysis. The ammonium excretion ability of nitrogen-fixing bacteria was determined by indigo blue-spectrophotometry. The activity of nitrogenase was determined by acetylene reduction method. [results] A nitrogen-fixing strain GXGL-4A was isolated from the roots of maize. The results of Gram staining showed that the strain had 95% similarity with Kosakonia oryzae Fo8A1d 16S rRNA gene sequence. It was named K. radicincitans GXGL-4A combined with morphological, physiological and biochemical characteristics and genome scanning. The expected 296bp band of nitrogen-fixing gene nif H was obtained by PCR, and the ammonium nitrogen content in fermentation broth was 2.5 mg / L by indigo blue spectrophotometry, which indicated that the strain had better ability to secrete ammonium. The activity of nitrogenase of GXGL-4A was measured by acetylene reduction method. The results showed that GXGL-4A strain could effectively reduce acetylene on nitrogen-free medium, and reached 232.94 nmol C2H4 / (mL h). [conclusion] GXGL-4A was a new nitrogen-fixing bacteria which could secrete ammonium well. It has good research value.
【作者单位】：上海交通大学农业与生物学院农业部都市农业(南方)重点实验室;
【基金】：国家重点基础研究发展规划项目(973计划)(No.2015CB755702)~~
【分类号】：S513;S182

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