Identification of nodulation promoter (nod-box) regions of Rhizobium galegae.
A hybridisation analysis of a genomic clone library of Rhizobium galegae HAMBI 1174 located four EcoRI fragments homologous to the nod-box promoter sequence of Sinorhizobium meliloti in two separate gene regions. Two of the five nod-boxes detected in the R. galegae genome were carried on a single cosmid clone, pRg30, upstream from the nodABCIJ and nodF genes, whereas the other three nod-boxes were carried on a different cosmid clone, pRg10. Hybridisations with various nod gene probes from S. meliloti and Rhizobium leguminosarum species detected a nodD homolog in pRg10. The sequence data obtained from regions adjacent to each nod-box in pRg10 confirmed the presence of a second nodD in the R. galegae genome and, in addition, revealed the presence of nodN, nodU, dctA nifH and nifQ-like genes in pRg10. Thus, by using a promoter-specific nod-box probe we could identify a new region carrying genes involved in nitrogen fixation and host specificity functions.
Suominen
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Department of Applied Chemistry and Microbiology, Helsinki University, Finland. Leena.Suominen@Helsinki.fi
Paulin
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Saano
A
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Saren
A M
AM
Tas
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Lindström
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K
D001483:Base Sequence; D003360:Cosmids; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009586:Nitrogen Fixation; D018517:Plant Roots / Q000382:microbiology*; D011401:Promoter Regions, Genetic; D015183:Restriction Mapping; D012231:Rhizobium / Q000235:genetics*; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D013559:Symbiosis / Q000235:genetics*