巴西固氮螺菌中两个影响胞外多糖合成的基因座的质粒定位与图谱分析。

Plasmid localization and mapping of two Azospirillum brasilense loci that affect exopolysaccharide synthesis.

作者信息

Michiels K, De Troch P, Onyeocha I, Van Gool A, Elmerich C, Vanderleyden J

机构信息

F. A. Janssens Memorial Laboratory for Genetics, Catholic University of Leuven, Heverlee, Belgium.

出版信息

Plasmid. 1989 Mar;21(2):142-6. doi: 10.1016/0147-619x(89)90058-9.

DOI:10.1016/0147-619x(89)90058-9

PMID:2544914

Abstract

Two Azospirillum brasilense loci that correct Rhizobium meliloti exoB and exoC mutants for exopolysaccharide (EPS) synthesis have been identified previously (K. W. Michiels, J. Vanderleyden, A. P. Van Gool, E. R. Signer, J. Bacteriol., 1988b). A. brasilense exo mutants produce EPS of lower molecular weight than the wild type strain. Here, we show by hybridization that these exo loci are located on a 90-MDa plasmid in A. brasilense Sp7. In four other Azospirillum strains but not in A. lipoferum SpBr17, the loci are likewise located on a plasmid of approximately the same size. Transposon Tn5 insertions in these loci were isolated and mapped on the cloned DNA by restriction analysis. Hybridization of restriction digests of purified 90-MDa plasmid DNA with probes containing the exo loci confirmed their plasmid location. This is the first report on plasmid localization of genes in Azospirillum.

摘要

先前已鉴定出巴西固氮螺菌的两个位点，它们可校正苜蓿根瘤菌exoB和exoC突变体的胞外多糖（EPS）合成（K. W. 米歇尔斯、J. 范德雷登、A. P. 范古尔、E. R. 西格纳，《细菌学杂志》，1988年b期）。巴西固氮螺菌exo突变体产生的EPS分子量低于野生型菌株。在此，我们通过杂交表明，这些exo位点位于巴西固氮螺菌Sp7的一个90-MDa质粒上。在其他四种固氮螺菌菌株中，但在脂环固氮螺菌SpBr17中未发现，这些位点同样位于大小大致相同的质粒上。分离出这些位点中的转座子Tn5插入，并通过限制酶分析将其定位在克隆的DNA上。用含有exo位点的探针与纯化的90-MDa质粒DNA的限制酶消化产物进行杂交，证实了它们在质粒上的位置。这是关于固氮螺菌中基因质粒定位的首次报道。