A Lipopolysaccharide Mutant of<i>Bradyrhizobium japonicum</i>that Uncouples Plant from Bacterial Differentiation

Stacey, Gary; So, Jae-Seong; Roth, L. E.; Carlson, R. W.

doi:10.1094/mpmi-4-332

Cited by 76 publications

(66 citation statements)

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“…Nevertheless, the majority of the LPS mutants can invade plant tissue more or less, suggesting that LPS is particularly important in later stage of symbiosis. Up to now, the most severe impairments in nodulation were reported in mutants deficient in O-chain (73,98). Significance of lipid A in symbiosis remains unclear because most of lipid A mutants show weak phenotypes such as delay and reduced competitiveness for nodulation (93,112) or sometimes no apparent symbiotic lesion (46,111).…”

Section: Determinants Of Rhizobium Symbiosismentioning

confidence: 99%

The Determinants of the Actinorhizal Symbiosis

Kucho

Hay²,

Normand³

2010

Microb. Environ.

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The actinorhizal symbiosis is a major contributor to the global nitrogen budget, playing a dominant role in ecological successions following disturbances. The mechanisms involved are still poorly known but there emerges the vision that on the plant side, the kinases that transmit the symbiotic signal are conserved with those involved in the transmission of the Rhizobium Nod signal in legumes. However, on the microbial side, complementation with Frankia DNA of Rhizobium nod mutants failed to permit identification of symbiotic genes. Furthermore, analysis of three Frankia genomes failed to permit identification of canonical nod genes and revealed symbiosis-associated genes such as nif, hup, suf and shc to be spread around the genomes. The present review explores some recently published approaches aimed at identifying bacterial symbiotic determinants.

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Section: Determinants Of Rhizobium Symbiosismentioning

confidence: 99%

The Determinants of the Actinorhizal Symbiosis

Kucho

Hay²,

Normand³

2010

Microb. Environ.

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“…The surface polysaccharides, including the lipopolysaccharides (LPSs), 1 are involved in the normal infection process. Mutants that lack the O-chain polysaccharide portion of their LPSs are symbiotically defective in that they are unable to form normal infection threads (1,2), and/or they cannot invade the root nodule cells (3)(4)(5). In addition, it has been shown that structural changes in the LPS occur during symbiotic infection and that most of these changes appear to take place in the O-chain polysaccharide portion of the LPS (6 -14).…”

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confidence: 99%

The Structures of the Lipopolysaccharides from Rhizobium etli Strains CE358 and CE359

Forsberg

Carlson

1998

Journal of Biological Chemistry

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The structural arrangement of oligosaccharides comprising the core region of Rhizobium etli CE3 lipopolysaccharide (LPS) has been elucidated through the characterization of the LPSs from two R. etli mutants. One mutant, CE358, completely lacks the O-chain polysaccharide, while the second mutant, CE359, contains a truncated portion of this polysaccharide. This structural arrangement of the core oligosaccharides in these LPSs was determined using electrospray ionization mass spectrometry, tandem mass spectrometry, and methylation analysis. Mild acid hydrolysis of the CE359 LPS produces two major core oligosaccharides: a tetrasaccharide (1) with the structure ␣-D-Galp- (136) Bacteria belonging to the family Rhizobiaceae are Gram-negative and are able to form nitrogen-fixing symbiotic relationships with legume plants. The surface polysaccharides, including the lipopolysaccharides (LPSs), 1 are involved in the normal infection process. Mutants that lack the O-chain polysaccharide portion of their LPSs are symbiotically defective in that they are unable to form normal infection threads (1, 2), and/or they cannot invade the root nodule cells (3-5). In addition, it has been shown that structural changes in the LPS occur during symbiotic infection and that most of these changes appear to take place in the O-chain polysaccharide portion of the LPS (6 -14). These structural adaptations in response to the environment of the host plant are likely to be important in order for the symbiont bacterium to induce a nitrogen-fixing nodule.In addition to the importance of determining the symbiotic "virulence" of these bacteria, rhizobial LPSs can have unique structural features compared with the LPSs from enteric bacteria. The most studied LPSs, the topic of this report, are those from Rhizobium etli and Rhizobium leguminosarum. All of the LPSs examined from wild-type or parent strains of these species are devoid of phosphate. Their lipid A region has a trisaccharide backbone consisting of one each of galacturonosyl (GalA), GlcN, and 2-aminogluconosyl (GlcN-onate) residues, the latter two residues being O-and N-acylated with ␤-hydroxy fatty acids and one very long chain fatty acid, 27-hydroxyoctacosanoic acid (15). This lipid A also appears not to carry any acyloxylacyl substituents. The core region has been found to consist of two oligosaccharides (16, 17) as shown below.

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“…Recent studies indicate involvement of LPSs at a later stage in the nodule development. Mutants which do not have the 0-chain region either fail to form normal infection threads or are not released properly from the infection thread into the host root cells (7,13,19,33,34,37).Using monoclonal antibodies to Rhizobium leguminosarum bv. viciae bacteroids, it has been shown that there are changes in LPS epitopes which occur during differentiation of bacteria into bacteroids (6,35,39,42).…”

mentioning

confidence: 99%

mentioning

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Chemical characterization of pH-dependent structural epitopes of lipopolysaccharides from Rhizobium leguminosarum biovar phaseoli

Bhat

Carlson

1992

J Bacteriol

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Lipopolysaccharide (LPS) was isolated from free-living Rhizobium leguminosarum bv. phaseoli CE3 cells grown at pH 4.8 (antigenically similar to bacteroid LPS) and compared with that from cells grown at pH 7.2 (free-living bacteria). Composition analysis revealed that pH 7.2 LPS differs from pH 4.8 LPS in that 2,3,4-tri-O-methylfucose is replaced by 2,3-di-0-methylfucose. The amount of 2-O-methylrhamnose is greater in the pH 4.8 LPS than in the pH 7.2 LPS. Analysis of the structural components of LPS (0-chain polysaccharide, core oligosaccharides, and the lipid A) revealed that all the composition differences in the various LPSs occur in the 0-chain polysaccharide. These structural variations between pH 4.8 and pH 7.2 LPSs provide a chemical basis for the observed lack of cross-reactivity with pH 4.8 LPS of two monoclonal antibodies, JIM28 and JIM29, raised against free-living bacteria grown at pH 7.2. An LPS preparation isolated from bacteroids contained both 2,3,4-tri-O-and 2,3-di-O-methylfucose residues. This result is consistent with the finding that the two monoclonal antibodies react weakly with bacteroid LPS. It is concluded that methylation changes occur on the LPS 0-chain of R. leguminosarum bv. phaseoli when the bacteria are grown at low pH and during nodule development.Rhizobia are gram-negative soil bacteria that form nitrogen-fixing symbiotic associations with leguminous plants. In terms of host selection, the bacteria exhibit a great deal of specificity. The surface carbohydrates of rhizobia, which include the lipopolysaccharide (LPS), extracellular polysaccharide, and capsular polysaccharide, have all been hypothesized to play a role in symbiosis (9,11,18,20,22,23). The LPSs of Rhizobium species resemble their enterobacterial counterparts in having structurally distinct regions; the 0-chain polysaccharide, the core oligosaccharide, and the hydrophobic lipid A (10, 13-17); however, there are many differences in the structural details of Rhizobium LPSs compared with enterobacterial LPSs (1-3, 12, 25-27).Earlier reports on the role of LPSs in symbiosis were directed toward the possibility that LPSs were involved in the specific attachment of the symbiont to the host plant (8,9,30). Recent studies indicate involvement of LPSs at a later stage in the nodule development. Mutants which do not have the 0-chain region either fail to form normal infection threads or are not released properly from the infection thread into the host root cells (7,13,19,33,34,37).Using monoclonal antibodies to Rhizobium leguminosarum bv. viciae bacteroids, it has been shown that there are changes in LPS epitopes which occur during differentiation of bacteria into bacteroids (6,35,39,42). Some of these changes can be produced ex planta, by growing the bacteria at low pH or low 02 tension, conditions which mimic, in part, the microenvironment of the root nodule (28). Similar results have been obtained for another strain of R. leguminosarum bv. viciae and for R leguminosarum bv. phaseoli (21, 38). These epitope changes occur only ...

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A Lipopolysaccharide Mutant ofBradyrhizobium japonicumthat Uncouples Plant from Bacterial Differentiation

Cited by 76 publications

References 0 publications

The Determinants of the Actinorhizal Symbiosis

The Determinants of the Actinorhizal Symbiosis

The Structures of the Lipopolysaccharides from Rhizobium etli Strains CE358 and CE359

Chemical characterization of pH-dependent structural epitopes of lipopolysaccharides from Rhizobium leguminosarum biovar phaseoli

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