Abstract
Rhizobium fredii participates in a nitrogen-fixing symbiosis with soybeans, in a strain-cultivar-specific interaction, and past studies have shown that the cell surface and extracellular polysaccharides of rhizobia function in the infection process that leads to symbiosis. The structural analysis of the capsular polysaccharides (K antigens) from strain USDA257 was performed in this study. The K antigens were extracted from cultured cells with hot phenol-water and purified by size exclusion chromatography. We isolated two structurally distinct K antigens, both containing a high proportion of 3-deoxy-D-manno-2-octulosonic acid (Kdo). The polysaccharides were characterized by matrix-assisted laser desorption ionization-time-of-flight-mass spectrometry, nuclear magnetic resonance spectrometry, and gas chromatography-mass spectrometry analyses. The primary polysaccharide, which constituted about 60% of the K-antigen preparation, consisted of repeating units of mannose (Man) and Kdo, [-->)3-beta-D-Manp-(1-->5)-beta-D-Kdop-(2-->], and a second polysaccharide consisted of 2-O-MeMan and Kdo, [-->)3-beta-D-2-O-MeManp-(1-->5)-beta-D-Kdop-(2-->]. These structures are similar to yet distinct from those of other strains of R. fredii and R. meliloti, and this finding provides further evidence that the K antigens of rhizobia are strain-specific antigens which are produced within a conserved motif.
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- Balatti P. A., Pueppke S. G. Cultivar-Specific Interactions of Soybean with Rhizobium fredii Are Regulated by the Genotype of the Root. Plant Physiol. 1990 Dec;94(4):1907–1909. doi: 10.1104/pp.94.4.1907. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Balatti P. A., Pueppke S. G. Nodulation of Soybean by a Transposon-Mutant of Rhizobium fredii USDA257 Is Subject to Competitive Nodulation Blocking by Other Rhizobia. Plant Physiol. 1990 Nov;94(3):1276–1281. doi: 10.1104/pp.94.3.1276. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Battisti L., Lara J. C., Leigh J. A. Specific oligosaccharide form of the Rhizobium meliloti exopolysaccharide promotes nodule invasion in alfalfa. Proc Natl Acad Sci U S A. 1992 Jun 15;89(12):5625–5629. doi: 10.1073/pnas.89.12.5625. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Blumenkrantz N., Asboe-Hansen G. New method for quantitative determination of uronic acids. Anal Biochem. 1973 Aug;54(2):484–489. doi: 10.1016/0003-2697(73)90377-1. [DOI] [PubMed] [Google Scholar]
- Carlson R. W., Price N. P., Stacey G. The biosynthesis of rhizobial lipo-oligosaccharide nodulation signal molecules. Mol Plant Microbe Interact. 1994 Nov-Dec;7(6):684–695. doi: 10.1094/mpmi-7-0684. [DOI] [PubMed] [Google Scholar]
- González J. E., Reuhs B. L., Walker G. C. Low molecular weight EPS II of Rhizobium meliloti allows nodule invasion in Medicago sativa. Proc Natl Acad Sci U S A. 1996 Aug 6;93(16):8636–8641. doi: 10.1073/pnas.93.16.8636. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kovács L. G., Balatti P. A., Krishnan H. B., Pueppke S. G. Transcriptional organization and expression of noIXWBTUV, a locus that regulates cultivar-specific nodulation of soybean by Rhizobium fredii USDA257. Mol Microbiol. 1995 Sep;17(5):923–933. doi: 10.1111/j.1365-2958.1995.mmi_17050923.x. [DOI] [PubMed] [Google Scholar]
- Krishnan H. B., Pueppke S. G. Flavonoid inducers of nodulation genes stimulate Rhizobium fredii USDA257 to export proteins into the environment. Mol Plant Microbe Interact. 1993 Jan-Feb;6(1):107–113. doi: 10.1094/mpmi-6-107. [DOI] [PubMed] [Google Scholar]
- Leigh J. A., Coplin D. L. Exopolysaccharides in plant-bacterial interactions. Annu Rev Microbiol. 1992;46:307–346. doi: 10.1146/annurev.mi.46.100192.001515. [DOI] [PubMed] [Google Scholar]
- Leigh J. A., Signer E. R., Walker G. C. Exopolysaccharide-deficient mutants of Rhizobium meliloti that form ineffective nodules. Proc Natl Acad Sci U S A. 1985 Sep;82(18):6231–6235. doi: 10.1073/pnas.82.18.6231. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lenter M., Jann B., Jann K. Structure of the K16 antigen from Escherichia coli O7:K16:H-, a Kdo-containing capsular polysaccharide. Carbohydr Res. 1990 Mar 25;197:197–204. doi: 10.1016/0008-6215(90)84142-h. [DOI] [PubMed] [Google Scholar]
- Meinhardt L. W., Krishnan H. B., Balatti P. A., Pueppke S. G. Molecular cloning and characterization of a sym plasmid locus that regulates cultivar-specific nodulation of soybean by Rhizobium fredii USDA257. Mol Microbiol. 1993 Jul;9(1):17–29. doi: 10.1111/j.1365-2958.1993.tb01665.x. [DOI] [PubMed] [Google Scholar]
- Reuhs B. L., Carlson R. W., Kim J. S. Rhizobium fredii and Rhizobium meliloti produce 3-deoxy-D-manno-2-octulosonic acid-containing polysaccharides that are structurally analogous to group II K antigens (capsular polysaccharides) found in Escherichia coli. J Bacteriol. 1993 Jun;175(11):3570–3580. doi: 10.1128/jb.175.11.3570-3580.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Reuhs B. L., Kim J. S., Badgett A., Carlson R. W. Production of cell-associated polysaccharides of Rhizobium fredii USDA205 is modulated by apigenin and host root extract. Mol Plant Microbe Interact. 1994 Mar-Apr;7(2):240–247. doi: 10.1094/mpmi-7-0240. [DOI] [PubMed] [Google Scholar]
- Reuhs B. L., Williams M. N., Kim J. S., Carlson R. W., Côté F. Suppression of the Fix- phenotype of Rhizobium meliloti exoB mutants by lpsZ is correlated to a modified expression of the K polysaccharide. J Bacteriol. 1995 Aug;177(15):4289–4296. doi: 10.1128/jb.177.15.4289-4296.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
- WEISSBACH A., HURWITZ J. The formation of 2-keto-3-deoxyheptonic acid in extracts of Escherichia coli B. I. Identification. J Biol Chem. 1959 Apr;234(4):705–709. [PubMed] [Google Scholar]