词典 / 微生物学

巴西固氮螺菌

Azospirillum brasilense

    Azospirillum brasilense is a nitrogen-fixing microorganism that has a potential use as an inoculant for promoting plant growth in grass and cereals. A. brasilense Yu62 which was isolated from the rhizosphere of maize in Beijing, China, is able to produce more than 50μg/ml IAA into the medium supplemented with exogenous Trp. To bring more information about synthesis and regulation of indole-3-acetic acid (IAA) from A. brasilense, a Tn5-insertion library of A. brasilense Yu62 was constructed and subjected to ...
            巴西固氮螺菌(Azospirillum brasilense)是一种能够促进草类和谷物生长的,具有固氮能力的根际促生长细菌。A.brasilense Yu62从北京郊区的玉米根际分离获得,在添加了色氨酸的培养基中能够合成超过50μg/ml的吲哚-3-乙酸(IAA)。为了更清楚的了解A.brasilense产IAA的合成机理,我们通过Tn5转座子诱变的方法获得了5,000多株具有卡那抗性的接合突变株,将这5,000多株突变株分别接种在MAZ培养基中摇瓶培养,用比色法和HPLC方法测定菌液中的IAA含量,得到了5个IAA产量降低的突变株。以转座子内的luxAB基因为探针进行Southern杂交,结果每个突变株都只有一条杂交带,证明这5个突变株都是Tn5单拷贝插入的突变体。测序及同源性比较表明,在这5个IAA产量降低的突变株中,被插入失活的基因分别为编码GntR家族的转录调节因子的atrA基因、编码ABC型Fe~(3+)转移系统中的离子结合蛋白的ftsA基因、编码外膜蛋白的omaA基因,编码醛脱氢酶的aldA基因及编码邻氨基苯甲酸合成酶组分Ⅰ的trpE基因。互补实验表明携带atrA、ftsA和omaA基因的广宿...

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