Abstract
Lima bean (Phaseolus lunatus L.) plants inoculated with Bradyrhizobium sp. strain 127E14 displayed a period of marked internode elongation that was not observed in plants inoculated with other compatible bradyrhizobia, including strain 127E15. When strain 127E14 nodulated an alternate host, cowpea (Vigna unguiculata L. Walp), a similar, although less dramatic growth response induced by the bacteria was observed. It has been speculated that the elongative growth promotion brought about by inoculation with strain 127E14 is mediated by gibberellins (GAs). Using deuterated internal standards and gas chromatography-mass spectroscopy analysis, we have quantified the levels of GA(1), GA(20), GA(19), and GA(44) in nodules and stems of two varieties of lima bean (bush and pole) and one variety of cowpea that were inoculated with either strain 127E14 or 127E15. In nodules formed by strain 127E14 on lima bean, endogenous levels of GA(20) and GA(19) were 10 to 40 times higher (35-88 ng/g dry weight) than amounts found in nodules formed by strain 127E15 (2.2-3.9 ng/g dry weight). Relative amounts of GA(44) were also higher (4- to 11-fold) in 127E14 nodules, but this increase was less pronounced. The rhizobial-induced increase of these GAs in the nodule occurred in both pole and bush varieties and seemed to be independent of host morphology. Regardless of rhizobial inoculum, levels of the "bioactive" GA(1) in the nodule (0.3-1.1 ng/g dry weight) were similar. In cowpea nodules, a similar, although smaller, difference in GA content due to rhizobial strain was observed. The concentration of GA(1) in lima bean stems was generally higher than that observed in the nodule, whereas concentrations of the other GAs measured were lower. In contrast with the nodule, GA concentrations in lima bean stems were not greater in plants inoculated with strain 127E14, and in some cases the slower growing plants inoculated with strain 127E15 actually had higher levels of GA(20), GA(19), and GA(44). Thus, there were major differences in concentrations of the precursors to GA(1) in nodules formed by the two bacterial strains, which were positively correlated with the observed elongation growth. These results support the hypothesis that the rhizobial strain modifies the endogenous GA status of the symbiotic system. This alteration in GA balance within the plant, presumably, underlies the observed growth response.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 12
Claim · model-written summary
127E14 induced lima bean internode elongation absent with other strains.
- Taxon
- Lima bean
Phaseolus lunatuse0 - Treatment
- inoculated with Bradyrhizobium sp. strain 127E14e0
- Interactor
- Bradyrhizobium sp. strain 127E14
Bradyrhizobium sp.e0symbiont - Outcome
- internode elongatione0
- Direction
- markede0
- Comparator
- other compatible bradyrhizobiae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Lima bean (Phaseolus lunatus L.) plants inoculated with Bradyrhizobium sp. strain 127E14 displayed a period of marked internode elongation that was not observed in plants inoculated with other compatible bradyrhizobia”
Claim · model-written summary
127E14 induced a smaller growth response in cowpea.
- Taxon
- cowpea
Vigna unguiculatae0 - Outcome
- growth responsee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“cowpea (Vigna unguiculata L. Walp), a similar, although less dramatic growth response induced by the bacteria was observed”
Claim · model-written summary
127E14 nodules had 10 to 40 times higher GA(20) and GA(19) than 127E15 nodules.
- Taxon
- lima beanPhaseolus lunatuse0
- Treatment
- strain 127E14e0
- Interactor
- strain 127E14e0symbiont
- Outcome
- endogenous levels of GA(20) and GA(19)e0
- Direction
- highere0
- Value
- 10 to 40 timese0
- Comparator
- strain 127E15e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In nodules formed by strain 127E14 on lima bean, endogenous levels of GA(20) and GA(19) were 10 to 40 times higher (35-88 ng/g dry weight) than amounts found in nodules formed by strain 127E15 (2.2-3.9 ng/g dry weight)”
Claim · model-written summary
GA(44) was four- to elevenfold higher in 127E14 nodules.
- Taxon
- lima beanPhaseolus lunatuse1
- Treatment
- 127E14e0
- Interactor
- 127E14e0symbiont
- Outcome
- Relative amounts of GA(44)e0
- Direction
- highere0
- Value
- 4- to 11-folde0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Relative amounts of GA(44) were also higher (4- to 11-fold) in 127E14 nodules”
t0“Legume-Rhizobium Symbiosis”
e1“two varieties of lima bean (bush and pole)”
Claim · model-written summary
The nodule GA increase occurred in pole and bush varieties.
- Taxon
- lima beanPhaseolus lunatuse1
- Outcome
- increase of these GAs in the nodulee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“rhizobial-induced increase of these GAs in the nodule occurred in both pole and bush varieties”
t0“Legume-Rhizobium Symbiosis”
e1“two varieties of lima bean (bush and pole)”
Claim · model-written summary
Nodule GA(1) levels were similar across inocula.
- Taxon
- lima beanPhaseolus lunatuse1
- Treatment
- rhizobial inoculume0
- Outcome
- levels of the "bioactive" GA(1) in the nodulee0
- Direction
- similare0
- Value
- 0.3-1.1 ng/g dry weighte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Regardless of rhizobial inoculum, levels of the "bioactive" GA(1) in the nodule (0.3-1.1 ng/g dry weight) were similar”
t0“Legume-Rhizobium Symbiosis”
e1“two varieties of lima bean (bush and pole)”
Claim · model-written summary
Cowpea nodules showed a smaller strain difference in GA content.
- Taxon
- cowpeaVigna unguiculatae0
- Outcome
- difference in GA contente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In cowpea nodules, a similar, although smaller, difference in GA content due to rhizobial strain was observed”
Claim · model-written summary
Lima bean stem GA(1) exceeded nodule GA(1).
- Taxon
- lima beanPhaseolus lunatuse0
- Outcome
- concentration of GA(1)e0
- Direction
- highere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“concentration of GA(1) in lima bean stems was generally higher than that observed in the nodule”
Claim · model-written summary
Other GA concentrations were lower in stems.
- Taxon
- lima beanPhaseolus lunatuse1
- Outcome
- concentrations of the other GAse0
- Direction
- lowere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“concentrations of the other GAs measured were lower”
t0“Legume-Rhizobium Symbiosis”
e1“two varieties of lima bean (bush and pole)”
Claim · model-written summary
Stem GA concentrations were not greater after 127E14 inoculation.
- Taxon
- lima beanPhaseolus lunatuse0
- Treatment
- strain 127E14e0
- Interactor
- strain 127E14e0symbiont
- Outcome
- GA concentrations in lima bean stemse0
- Direction
- not greatere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“GA concentrations in lima bean stems were not greater in plants inoculated with strain 127E14”
Claim · model-written summary
Some slower growing 127E15 plants had higher GA(20), GA(19), and GA(44).
- Taxon
- lima beanPhaseolus lunatuse1
- Outcome
- levels of GA(20), GA(19), and GA(44)e0
- Direction
- highere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“slower growing plants inoculated with strain 127E15 actually had higher levels of GA(20), GA(19), and GA(44)”
t0“Legume-Rhizobium Symbiosis”
e1“two varieties of lima bean (bush and pole)”
Claim · model-written summary
Nodule GA precursor concentrations correlated with elongation growth.
- Taxon
- lima beanPhaseolus lunatuse1
- Organ / stage
- nodulese0
- Outcome
- elongation growthe0
- Direction
- positively correlatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“concentrations of the precursors to GA(1) in nodules formed by the two bacterial strains, which were positively correlated with the observed elongation growth”
t0“Legume-Rhizobium Symbiosis”
e1“two varieties of lima bean (bush and pole)”
The same questions in other papers
inoculation · symbiosis · Phaseolus lunatus (lima bean)Positive and negative results
2 in the opposite direction
- positive
- positive
inoculation · growth · Phaseolus lunatus (lima bean)Results agree
5 papers in the same direction as this paper
- positive
- positive
- positive
2 papers more in this group
See all 6 papers →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.