用发光酶基因(luxAB)标记法研究慢生花生根瘤菌的竞争结瘤能力

luxAB基因标记是一种新型基因标记技术，在很多研究领域都有着良好的应用前景。研究通过三亲本杂交将luxAB基因成功地向慢生型花生根瘤菌进行了转移，并获得了一株带LuxAB基因标记的菌株Cspr7-1。对Cspr7-1进行性状、标记基因的遗传稳定性检测，结果表明，LuxAB基因不仅能有效表达，而且性状稳定。在无氮水培条件下进行标记菌株与土著根瘤菌的竞争结瘤试验。结果证实，Cspr7-1在植物根系上的占瘤率平均达到61.3％，比土著根瘤菌的竞争结瘤能力强，而且Cspr7-1在主根上的侵染能力远较侧根上的强，平均高出22.3％-39.6％。

The competitiveness of Bradyrhizobium sp. (Arachis) studied by using luxAB marker gene technique

The luxAB marker gene is useful in microbial ecological studies. One strain Cspr7-1 marked with luxAB gene was obtained triumphantly by thri-patental mating. Detecting the characteristic and stability of Cspr7-1,the results showed that: the luxAB gene not only expressed in Cspr7-1, but also kept stabilized.Using the luxAB marked gene to study competitive ability of Cspr7-1 with soil indigenous rhizobia in N-free solution pot, we found that the Cspr7-1 had higher nitrogen fixing efficiency and stronger competitive ability than that of the soil indigenous bradyrhizobia. Nodule occupancy of Cspr7-1 on peant root was 61.3% on average.The competitive ability of Cspr7-1 was different between main root and lateral root.