Use of a promoter-specific probe to identify two loci from the Rhizobium meliloti nodulation regulon
- 1 February 1989
- journal article
- research article
- Published by Springer Nature in Plant Molecular Biology
- Vol. 12 (2) , 181-188
- https://doi.org/10.1007/bf00020503
Abstract
The nodulation regulon of Rhizobium meliloti AK631 includes several operons (nodABC, hsnABC, hsnD, efn locus) which have in common a consensus promoter sequence called the nod box. A synthetic nod box probe was used to identify two additional nod boxes, n4 and n5, which were subcloned for study. By constructing lac fusions, we show that n4 and n5 sponsor induction of downstream regions as previously shown for n1-nodABC and n2-hsnABC. Using site-directed Tn5 mutagenesis, we find that the n5 locus plays a significant role in nodulation of alfalfa and sweetclover, whereas the n4 locus is important for alfalfa, but not for sweetclover. Hybridization data suggest that the n5 locus is conserved among Rhizobium species. In contrast, the n4 locus seems to be unique to Rhizobium meliloti strains, in agreement with the host-specific phenotype of n4 locus mutants. Thus, the use of a promoter probe allows us to identify nodulation genes which may be overlooked by standard methods such as random Tn5 mutagenesis.Keywords
This publication has 29 references indexed in Scilit:
- Mini-Mulac transposons with broad-host-range origins of conjugal transfer and replication designed for gene regulation studies in RhizobiaceaeGene, 1988
- At least two nodD genes are necessary for efficient nodulation of alfalfa by Rhizobium melilotiJournal of Molecular Biology, 1986
- Organization, structure and symbiotic function of rhizobium meliloti nodulation genes determining host specificity for alfalfaCell, 1986
- A portable DNA sequence carrying the cohesive site (cos) of bacteriophage λ and the mob (mobilization) region of the broad-host-range plasmid RK2: a module for the construction of new cosmidstGene, 1984
- Construction of improved M13 vectors using oligodeoxynucleotide-directed mutagenesisGene, 1983
- A general method for site-directed mutagenesis in prokaryotesNature, 1981
- Broad host range DNA cloning system for gram-negative bacteria: construction of a gene bank of Rhizobium meliloti.Proceedings of the National Academy of Sciences, 1980
- Genetic and Biochemical Analysis of Mutants Affected in Nitrate Reduction in Rhizobium melilotiJournal of General Microbiology, 1979
- R Factor Transfer in Rhizobium leguminosarumMicrobiology, 1974
- The Infection of Clover Root Hairs by Nodule Bacteria Studied by a Simple Glass Slide TechniqueMicrobiology, 1957