Abstract
Rhizobium meliloti nodulation (nod) genes required for specific infection and nodulation of alfalfa have been cloned. Transposon Tn5 mutagenesis defined three nod regions spanning 16 kilobases of the pSym megaplasmid. Genetic and cytological studies of 62 nodulation-defective mutants allowed the assignment of symbiotic developmental phenotypes to common and specific nod loci. Root hair curling was determined by both common (region I) and specific (region III) nod transcription units; locus IIIb (nodH gene) positively controlled curling on the homologous host alfalfa, whereas loci IIIa (nodFE) and IIIb (nodH) negatively controlled curling on heterologous hosts. Region I (nodABC) was required for bacterial penetration and infection thread initiation in shepherd's crooks, and the nodFE transcription unit controlled infection thread development within the alfalfa root hair. In contrast, induction of nodule organogenesis, which can be triggered from a distance, seemed to be controlled by common nodABC genes and not to require specific nod genes nodFE and nodH. Region II affected the efficiency of hair curling and infection thread formation.
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Claims 10
Claim · model-written summary
Rhizobium meliloti nod genes for alfalfa infection and nodulation were cloned.
- Taxon
- alfalfa
Medicago sativae0 - Gene
- nodulation (nod) genese0
- Outcome
- have been clonede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rhizobium meliloti nodulation (nod) genes required for specific infection and nodulation of alfalfa have been cloned.”
Claim · model-written summary
Mutagenesis defined three nod regions on the pSym megaplasmid.
- Taxon
- alfalfaMedicago sativae0
- Gene
- nod regionse0
- Outcome
- three nod regions spanning 16 kilobasese0
- Value
- 16 kilobasese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rhizobium meliloti nodulation (nod) genes required for specific infection and nodulation of alfalfa have been cloned. Transposon Tn5 mutagenesis defined three nod regions spanning 16 kilobases of the pSym megaplasmid.”
t0“Assignment of symbiotic developmental phenotypes to common and specific nodulation (nod) genetic loci of Rhizobium meliloti”
Claim · model-written summary
Both common and specific nod transcription units determined root hair curling.
Not reportedTaxon
Verbatim
e0“Root hair curling was determined by both common (region I) and specific (region III) nod transcription units”
Claim · model-written summary
nodH positively controlled root hair curling on alfalfa.
- Taxon
- alfalfaMedicago sativae0
- Gene
- nodH genee0
- Outcome
- curlinge0
- Direction
- positively controllede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“locus IIIb (nodH gene) positively controlled curling on the homologous host alfalfa”
Claim · model-written summary
nodFE and nodH negatively controlled curling on heterologous hosts.
Verbatim
e0“loci IIIa (nodFE) and IIIb (nodH) negatively controlled curling on heterologous hosts”
Claim · model-written summary
nodABC was required for bacterial penetration and infection thread initiation.
- Organ / stage
- shepherd's crookse0
- Gene
- nodABCe0
- Outcome
- bacterial penetration and infection thread initiatione0
Not reportedTaxon
Verbatim
e0“Region I (nodABC) was required for bacterial penetration and infection thread initiation in shepherd's crooks”
Claim · model-written summary
nodFE controlled infection thread development in alfalfa root hair.
- Taxon
- alfalfaMedicago sativae0
- Organ / stage
- root haire0
- Gene
- nodFEe0
- Outcome
- infection thread developmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the nodFE transcription unit controlled infection thread development within the alfalfa root hair”
Claim · model-written summary
Common nodABC genes appeared to control nodule organogenesis.
Not reportedTaxon
Verbatim
e0“induction of nodule organogenesis, which can be triggered from a distance, seemed to be controlled by common nodABC genes and not to require specific nod genes nodFE and nodH”
Claim · model-written summary
Nodule organogenesis appeared not to require nodFE and nodH.
Not reportedTaxon
Verbatim
e0“induction of nodule organogenesis, which can be triggered from a distance, seemed to be controlled by common nodABC genes and not to require specific nod genes nodFE and nodH”
Claim · model-written summary
Region II affected the efficiency of hair curling and infection thread formation.
Not reportedTaxon
Verbatim
e0“Region II affected the efficiency of hair curling and infection thread formation.”