Stimulation of adhesiveness, infectivity, and competitiveness for nodulation of Bradyrhizobium japonicum by its pretreatment with soybean seed lectin

Lodeiro, Aníbal Roberto

doi:10.1016/s0378-1097(00)00232-9

Cited by 28 publications

(53 citation statements)

References 21 publications

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“…SBL binding. SBL was isolated from soybean Promax seeds (kindly provided by A. Perticari, INTA, Argentina) by affinity column chromatography on ⑀-amino-caproyl-N-acetyl-D-galactosamine agarose; its purity was evaluated as described (30), and an aliquot from this preparation was labeled with fluorescein isothiocyanate (FITC) (5). Rhizobia were incubated with 60 g of FITC-SBL ml Ϫ1 for 30 min at 28°C without shaking.…”

Section: Methodsmentioning

confidence: 99%

“…For adsorption experiments, the procedure already described was followed (30). Briefly, 10 4-day-old soybean plants were incubated for 1 h at 28°C and 50 rpm shaking in 50 ml of N-free Fåhraeus solution (18) with approximately 10 4 SBL-treated B. japonicum 3001 per ml.…”

Section: Methodsmentioning

confidence: 99%

“…Total counts of visible microcolonies on all primary roots, expressed as the percentage of the total number of CFU present during the incubation, represent the adsorption index (%A). Stimulation of adsorption is the difference in %A between protein-treated and control rhizobia as a percentage of the %A of control rhizobia (30,55).…”

Section: Methodsmentioning

confidence: 99%

“…Nodulation profiles were obtained by inoculating 42 plants with approximately 5 ϫ 10 4 rhizobia plant Ϫ1 in plastic growth pouches watered with a modified N-free Fåhraeus solution (6,30). The nodule distribution along the primary roots was recorded after 10 days of growth in the greenhouse at 26°C/18°C day/night temperatures, with respect to the smallest emergent root hairs and the root tip positions at the time of inoculation.…”

Section: Methodsmentioning

confidence: 99%

“…In addition, some plant lectins, such as soybean lectin (SBL), are released into the rhizosphere (52,55) and specifically stimulate rhizobial adsorption and infection (30,55). Although the mechanism of plant lectin action remains obscure, its role in restricting rhizobium-host specificity range was demonstrated in studies with transgenic plants (15,52).…”

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confidence: 99%

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Improved Soybean Root Association of N-Starved Bradyrhizobium japonicum

et al. 2001

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In this study, we addressed the effects of N limitation in Bradyrhizobium japonicum for its association with soybean roots. The wild-type strain LP 3001 grew for six generations with a growth rate of 1.2 day ؊1 in a minimal medium with 28 mM mannitol as the carbon source and with the N source [(NH 4 ) 2 SO 4 ] limited to only 20 M. Under these conditions, the glutamine synthetase (GS) activity was five to six times higher than in similar cultures grown with 1 or 0.1 mM (NH 4 ) 2 SO 4 . The NtrBC-inducible GSII form of this enzyme accounted for 60% of the specific activity in N-starved rhizobia, being negligible in the other two cultures. The exopolysaccharide (EPS) and capsular polysaccharide (CPS) contents relative to cell protein were significantly higher in the N-starved cultures, but on the other hand, the poly-3-hydroxybutyrate level did not rise in comparison with N-sufficient cultures. In agreement with the accumulation of CPS in N-starved cultures, soybean lectin (SBL) binding as well as stimulation of rhizobial adsorption to soybean roots by SBL pretreatment were higher. The last effect was evident only in cultures that had not entered stationary phase. We also studied nodC gene induction in relation to N starvation. In the chromosomal nodC::lacZ fusion Bj110-573, nodC gene expression was induced by genistein 2.7-fold more in N-starved young cultures than in nonstarved ones. In stationary-phase cultures, nodC gene expression was similarly induced in N-limited cultures, but induction was negligible in cultures limited by another nutrient. Nodulation profiles obtained with strain LP 3001 grown under N starvation indicated that these cultures nodulated faster. In addition, as culture age increased, the nodulation efficiency decreased for two reasons: fewer nodules were formed, and nodulation was delayed. However, their relative importance was different according to the nutrient condition: in older cultures the overall decrease in the number of nodules was the main effect in N-starved cultures, whereas a delay in nodulation was more responsible for a loss in efficiency of N-sufficient cultures. Competition for nodulation was studied with young cultures of two wild-type strains differing only in their antibiotic resistance, the N-starved cultures being the most competitive.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Improved Soybean Root Association of N-Starved Bradyrhizobium japonicum

et al. 2001

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Kinetic sedimentation of Rhizobium-aggregates produced by leguminous lectins

Martínez

Netto

Figueiredo

et al. 2005

World J Microbiol Biotechnol

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Lectins from Canavalia brasiliensis (CnBr), Cratylia floribunda (CFL), Vatairea macrocarpa (VML) and Phaseolus vulgaris (PHA) aggregate Rhizobium bacteria. The relationship between specific sedimentation rate, m¢ (based on bacterial dry biomass) of bacterial aggregates and lectin concentrations was hyperbolic and showed bacterial surface affinity by lectins. R. tropici (Rt), R. leguminosarum bv. phaseoli (Rlp) and R. etli (Re) surfaces showed predominantly receptors of galactosidic nature. The Rt surfaces showed very high affinities (k s ¼ ±8.6 · 10 )8 ag lectin protein ml )1 ) by Gal-specific lectins (PHA and VML), and very low affinities (k s ¼ ±4.9 · 10 )6 ) by Glcspecific lectins (CnBr and CFL). The Rlp surface had intermediate affinities by lectins. The Re surface showed high affinities by PHA (k s ¼ ±1.26 · 10 )8 ) and intermediate affinities by VML, CnBr and CFL. The relationship between sedimentation specific m¢¢ (based on lectin weight) and bacterial density was a sigmoid and showed lectin affinity by Rt surfaces. The bacterial sedimentation showed positive cooperative binding of lectins. The V 00 max induced by Glc-specific lectins was ±20% of that produced by Gal-specific lectins. The PHA affinity (k s = 1.19 mg dry biomass ml )1 ) was larger than VML (k s = 1.23). The Glc-specific lectin affinities were smaller than those of Galspecific. The apparent binding site number of lectins (n app ) was: 2.7-PHA; 2.2-VML; 3.2-CFL and 3.2-CnBr. The dissociation constant, k s , of lectin-binding kinetics decreased with sugar-hapten treatment (10 lM). The n app decreased in PHA and CFL, increasing in VML + sugar-hapten treatment. This study showed that there is a difference in Rhizobium surfaces for lectin binding.

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Two effects of combined nitrogen on the adhesion of Rhizobium etli to bean roots

Pérez-Giménez

Lodeiro

2013

Symbiosis

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Combined forms of nitrogen negatively influence rhizobia-legume symbiosis. The effects of combined nitrogen are known for nodulation and dinitrogen (N 2 ) fixation, but little is known about the effect on preinfection events. Here, we studied the effects of combined nitrogen on the adhesion of Rhizobium etli to common bean (Phaseolus vulgaris L.) roots. When potassium nitrate (KNO 3 ) or sodium glutamate was added to an incubation mixture of rhizobia and plants that were previously grown in nitrogen-free solution, rhizobial adhesion to roots was stimulated. However, the rhizobial adhesion to bean roots that were previously grown with 10 mM KNO 3 was reduced by half. A fraction of the bean root exudates, which is thermolabile and has molecular mass larger than 12 kDa stimulated rhizobial adhesion, but this stimulatory activity was lost in root exudates obtained with 10 mM KNO 3 . Thus, the inhibition of symbiosis in response to combined nitrogen may be controlled by the plant at the preinfection stage as well.

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Stimulation of adhesiveness, infectivity, and competitiveness for nodulation of Bradyrhizobium japonicum by its pretreatment with soybean seed lectin

Cited by 28 publications

References 21 publications

Improved Soybean Root Association of N-Starved Bradyrhizobium japonicum

Improved Soybean Root Association of N-Starved Bradyrhizobium japonicum

Kinetic sedimentation of Rhizobium-aggregates produced by leguminous lectins

Two effects of combined nitrogen on the adhesion of Rhizobium etli to bean roots

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