Abstract
We examined the contribution of a cryptic plasmid, pRmeGR4b, to the nodulation of Medicago sativa by strain GR4 of Rhizobium meliloti. A 905-base-pair PstI DNA fragment in pRmeGR4b was found to hybridize DNA of the R. meliloti fixA promoter region as a probe. Sequence analysis of the PstI fragment showed a 206-base-pair region displaying high homology with the DNA upstream of the RNA start points of the P1 and P2 symbiotic promoters. Putative nif promoter consensus sequences were conserved in this DNA segment. Expression of DNA downstream of the nif promoterlike sequence, monitored by beta-galactosidase activity of different lacZ fusions, was demonstrated to depend on a functional nifA gene, both in microaerobically free-living cells and in nodules. Individual transposon Tn3-HoHo1 insertions in this DNA region caused a reduced nodulation competitiveness. This new symbiotic region, occupying approximately 5 kilobases of pRmeGR4b DNA, was called nfe (nodule formation efficiency).
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Claims 6
Claim · model-written summary
Tn3-HoHo1 insertions in the nfe DNA region reduced Rhizobium meliloti nodulation competitiveness on Medicago sativa.
- Taxon
- Medicago sativa
Medicago sativae1 - Material
- strain GR4e1
- Treatment
- Tn3-HoHo1 insertionse2
- Interactor
- Rhizobium meliloti
Sinorhizobium melilotie1symbiont - Outcome
- nodulation competitivenesse2
- Direction
- reducede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“We examined the contribution of a cryptic plasmid, pRmeGR4b, to the nodulation of Medicago sativa by strain GR4 of Rhizobium meliloti”
e2“Individual transposon Tn3-HoHo1 insertions in this DNA region caused a reduced nodulation competitiveness”
Claim · model-written summary
Expression downstream of the nif promoter-like sequence depends on a functional nifA gene in free-living cells and in nodules.
- Taxon
- Medicago sativaMedicago sativae1
- Gene
- nifAe3
- Outcome
- Expression of DNA downstream of the nif promoterlike sequencee3
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“We examined the contribution of a cryptic plasmid, pRmeGR4b, to the nodulation of Medicago sativa by strain GR4 of Rhizobium meliloti”
e3“Expression of DNA downstream of the nif promoterlike sequence, monitored by beta-galactosidase activity of different lacZ fusions, was demonstrated to depend on a functional nifA gene, both in microaerobically free-living cells and in nodules”
Claim · model-written summary
A 206-base-pair region of the pRmeGR4b PstI fragment shows high homology with the DNA upstream of the P1 and P2 symbiotic promoter RNA start points.
- Taxon
- Medicago sativaMedicago sativae1
- Outcome
- region displaying high homologye4
- Value
- 206-base-paire4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“We examined the contribution of a cryptic plasmid, pRmeGR4b, to the nodulation of Medicago sativa by strain GR4 of Rhizobium meliloti”
e4“Sequence analysis of the PstI fragment showed a 206-base-pair region displaying high homology with the DNA upstream of the RNA start points of the P1 and P2 symbiotic promoters”
Claim · model-written summary
A 905-base-pair PstI fragment of pRmeGR4b hybridized the Rhizobium meliloti fixA promoter region.
- Taxon
- Medicago sativaMedicago sativae1
- Outcome
- hybridize DNA of the R. meliloti fixA promoter regione5
- Value
- 905-base-paire5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“We examined the contribution of a cryptic plasmid, pRmeGR4b, to the nodulation of Medicago sativa by strain GR4 of Rhizobium meliloti”
e5“A 905-base-pair PstI DNA fragment in pRmeGR4b was found to hybridize DNA of the R. meliloti fixA promoter region as a probe”
Claim · model-written summary
Putative nif promoter consensus sequences were conserved in the DNA segment of the nfe region.
- Taxon
- Medicago sativaMedicago sativae1
- Outcome
- nif promoter consensus sequences were conservede6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“We examined the contribution of a cryptic plasmid, pRmeGR4b, to the nodulation of Medicago sativa by strain GR4 of Rhizobium meliloti”
e6“Putative nif promoter consensus sequences were conserved in this DNA segment”
Claim · model-written summary
The nfe symbiotic region occupies approximately 5 kilobases of pRmeGR4b DNA.
- Taxon
- Medicago sativaMedicago sativae1
- Outcome
- symbiotic regione7
- Value
- approximately 5 kilobasese7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“We examined the contribution of a cryptic plasmid, pRmeGR4b, to the nodulation of Medicago sativa by strain GR4 of Rhizobium meliloti”
e7“This new symbiotic region, occupying approximately 5 kilobases of pRmeGR4b DNA, was called nfe (nodule formation efficiency)”