Abstract
Host specificity in the Rhizobium-legume symbiosis is controlled in the bacterium by host specific nodulation (hsn) genes residing on its symbiotic plasmid. We have examined the structure of the major acidic heteropolysaccharide produced by recombinant hybrid strains of Rhizobium leguminosarum carrying cloned R. trifolii hsn genes with those produced by the parent donor and recipient strains. Alteration of the nod gene composition of R. leguminosarum strain 300 by introduction of an 8-kilobase set of hsn genes (nodFERL and nodMN) from R. trifolii strain ANU843, resulted in a hybrid strain which conferred efficient white clover infection and nodulation, production of the R. trifolii-type acidic polysaccharide, and an increased proportion of bacterial cells which bound to the white clover lectin, trifoliin A, in the external root environment. 1H NMR studies indicated that the structure of the polysaccharide from the hybrid recombinant differed from that of the R. leguminosarum strain 300 recipient in site and stoichiometry of acetate and stoichiometry of 3-hydroxybutyrate substituents. In contrast, the polysaccharide from a different hybrid recombinant strain containing only R. trifolii nodFERL genes had the acetylation pattern of the R. leguminosarum recipient but was substituted with 3-hydroxybutyrate at a level between that made by R. trifolii and R. leguminosarum. This latter recombinant strain displays sparse infection and nodulation of white clover roots. Immunofluorescence studies indicated that the R. leguminosarum recombinant strain containing the full complement of R. trifolii hsn genes (nodFERL and nodMN) gained the ability to interact with the excreted lectin, trifoliin A, in the white clover root environment, whereas the recombinant strain containing R. trifolii nodFERL only, was significantly attenuated in this cell-lectin interaction. These results indicate that the acylation pattern of the acidic polysaccharide synthesized by these hybrid recombinants of R. leguminosarum is influenced by the introduced hsn genes of R. trifolii and suggest that the acidic polysaccharide of R. trifolii and the interaction of these bacteria with the host lectin may contribute to host specificity in the white clover-R. trifolii symbiosis.
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Claims 9
Claim · model-written summary
The hybrid strain with R. trifolii hsn genes conferred efficient white clover infection and nodulation.
- Taxon
- white clover
Trifolium repense1 - Treatment
- introduction of an 8-kilobase set of hsn genes (nodFERL and nodMN) from R. trifolii strain ANU843e1
- Interactor
- R. trifolii
Rhizobium leguminosarume1symbiont - Outcome
- efficient white clover infection and nodulatione1
- Direction
- conferrede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“by introduction of an 8-kilobase set of hsn genes (nodFERL and nodMN) from R. trifolii strain ANU843, resulted in a hybrid strain which conferred efficient white clover infection and nodulation”
Claim · model-written summary
The hybrid strain produced the R. trifolii-type acidic polysaccharide.
- Taxon
- white cloverTrifolium repense1
- Interactor
- R. trifoliiRhizobium leguminosarume1symbiont
- Outcome
- production of the R. trifolii-type acidic polysaccharidee2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“by introduction of an 8-kilobase set of hsn genes (nodFERL and nodMN) from R. trifolii strain ANU843, resulted in a hybrid strain which conferred efficient white clover infection and nodulation”
e2“production of the R. trifolii-type acidic polysaccharide, and an increased proportion of bacterial cells which bound to the white clover lectin, trifoliin A, in the external root environment”
Claim · model-written summary
The hybrid strain with R. trifolii hsn genes had an increased proportion of bacterial cells bound to the white clover lectin trifoliin A in the external root environment.
- Taxon
- white cloverTrifolium repense1
- Treatment
- introduction of an 8-kilobase set of hsn genes (nodFERL and nodMN) from R. trifolii strain ANU843e1
- Interactor
- R. trifoliiRhizobium leguminosarume1symbiont
- Outcome
- proportion of bacterial cells which bound to the white clover lectine2
- Direction
- increasede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“by introduction of an 8-kilobase set of hsn genes (nodFERL and nodMN) from R. trifolii strain ANU843, resulted in a hybrid strain which conferred efficient white clover infection and nodulation”
e2“production of the R. trifolii-type acidic polysaccharide, and an increased proportion of bacterial cells which bound to the white clover lectin, trifoliin A, in the external root environment”
Claim · model-written summary
The polysaccharide of the hybrid recombinant differed from that of the R. leguminosarum recipient in acetate and 3-hydroxybutyrate substituents.
- Taxon
- white cloverTrifolium repense1
- Interactor
- R. leguminosarumRhizobium leguminosarume3symbiont
- Outcome
- site and stoichiometry of acetate and stoichiometry of 3-hydroxybutyrate substituentse3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“by introduction of an 8-kilobase set of hsn genes (nodFERL and nodMN) from R. trifolii strain ANU843, resulted in a hybrid strain which conferred efficient white clover infection and nodulation”
e3“1H NMR studies indicated that the structure of the polysaccharide from the hybrid recombinant differed from that of the R. leguminosarum strain 300 recipient in site and stoichiometry of acetate and stoichiometry of 3-hydroxybutyrate substituents”
Claim · model-written summary
The hybrid containing only R. trifolii nodFERL genes had the acetylation pattern of the R. leguminosarum recipient.
- Taxon
- white cloverTrifolium repense1
- Treatment
- containing only R. trifolii nodFERL genese4
- Outcome
- acetylation patterne4
- Direction
- no_changeinferrede4
- Comparator
- R. leguminosarum recipiente4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“by introduction of an 8-kilobase set of hsn genes (nodFERL and nodMN) from R. trifolii strain ANU843, resulted in a hybrid strain which conferred efficient white clover infection and nodulation”
e4“a different hybrid recombinant strain containing only R. trifolii nodFERL genes had the acetylation pattern of the R. leguminosarum recipient but was substituted with 3-hydroxybutyrate at a level between that made by R. trifolii and R. leguminosarum”
Claim · model-written summary
The hybrid containing only R. trifolii nodFERL genes was substituted with 3-hydroxybutyrate at a level between that of R. trifolii and R. leguminosarum.
- Taxon
- white cloverTrifolium repense1
- Outcome
- was substituted with 3-hydroxybutyratee4
- Qualifier
- at a level between that made by R. trifolii and R. leguminosarume4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“by introduction of an 8-kilobase set of hsn genes (nodFERL and nodMN) from R. trifolii strain ANU843, resulted in a hybrid strain which conferred efficient white clover infection and nodulation”
e4“a different hybrid recombinant strain containing only R. trifolii nodFERL genes had the acetylation pattern of the R. leguminosarum recipient but was substituted with 3-hydroxybutyrate at a level between that made by R. trifolii and R. leguminosarum”
Claim · model-written summary
The hybrid containing only R. trifolii nodFERL genes displays sparse infection and nodulation of white clover roots.
- Taxon
- white cloverTrifolium repense5
- Outcome
- sparse infection and nodulatione5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“by introduction of an 8-kilobase set of hsn genes (nodFERL and nodMN) from R. trifolii strain ANU843, resulted in a hybrid strain which conferred efficient white clover infection and nodulation”
e5“This latter recombinant strain displays sparse infection and nodulation of white clover roots”
Claim · model-written summary
The acidic polysaccharide of R. trifolii and its interaction with the host lectin may contribute to host specificity in the white clover-R. trifolii symbiosis.
- Taxon
- white cloverTrifolium repense0
- Interactor
- R. trifoliiRhizobium leguminosarume0symbiont
- Outcome
- host specificitye0
- Qualifier
- the interaction of these bacteria with the host lectine0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“suggest that the acidic polysaccharide of R. trifolii and the interaction of these bacteria with the host lectin may contribute to host specificity in the white clover-R. trifolii symbiosis”
Claim · model-written summary
The acylation pattern of the acidic polysaccharide is influenced by the introduced hsn genes of R. trifolii in white clover symbiosis.
- Taxon
- white cloverTrifolium repense1
- Treatment
- introduced hsn genes of R. trifoliie0
- Outcome
- acylation pattern of the acidic polysaccharidee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“by introduction of an 8-kilobase set of hsn genes (nodFERL and nodMN) from R. trifolii strain ANU843, resulted in a hybrid strain which conferred efficient white clover infection and nodulation”
e0“These results indicate that the acylation pattern of the acidic polysaccharide synthesized by these hybrid recombinants of R. leguminosarum is influenced by the introduced hsn genes of R. trifolii”
The same questions in other papers
Rhizobium leguminosarum · symbiosis · Trifolium repens (white clover)Positive and negative results
1 paper in the same direction as this paper · 2 in the opposite direction
- negative
- negative
- positive
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.