Separation of cyclic (1→2)-β-D-glucans (cyclosophoraoses) produced by agrobacterium and rhizobium, and determination of their degree of polymerization by high-performance liquid chromatography

Koizumi, Kyoko; Okada, Yasuyo; Horiyama, Shizuyo; Utamura, Toshiko; Hisamatsu, Makoto; Amemura, Akinori

doi:10.1016/s0021-9673(01)96701-9

Cited by 53 publications

(21 citation statements)

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“…Studies have demonstrated thatAgrobacterium and Rhizobium species synthesize periplasmic glucans with similar structures (3,10,16). In both genera, periplasmic glucans are composed of a cyclic 13-1,2-glucan backbone containing 17 to 24 glucose residues.…”

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confidence: 99%

Periplasmic glucans of Pseudomonas syringae pv. syringae

1994

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We report the initial characterization of glucans present in the periplasmic space of Pseudomonas syringae pv. syringae (strain R32). These compounds were found to be neutral, unsubstituted, and composed solely of glucose. Their size ranges from 6 to 13 glucose units/mol. Linkage studies and nuclear magnetic resonance analyses demonstrated that the glucans are linked by P-1,2 and jB-1,6 glycosidic bonds. In contrast to the periplasmic glucans found in other plant pathogenic bacteria, the glucans of P. syringae pv. syringae are not cyclic but are highly branched structures. Acetolysis studies demonstrated that the backbone consists of jB-1,2-4inked glucose units to which the branches are attached by 0-1,6 linkages. These periplasmic glucans were more abundant when the osmolarity of the growth medium was lower. Thus, P. syringae pv. syringae appears to synthesize periplasmic glucans in response to the osmolarity of the medium. The structural characteristics of these glucans are very similar to the membrane-derived oligosaccharides of Escherichia coli, apart from the neutral character, which contrasts with the highly anionic E. coli membrane-derived oligosaccharides.The Pseudomonas syringae group of plant pathogenic bacteria contains various pathogens that cause diseases on the foliage of plants. These bacteria are mainly differentiated by the host plants in which they are capable of multiplying and causing disease. P. syingae pv. syringae is the causal agent of brown spot disease of Phaseolus vulgaris, the common bean.Isolation of mutants that were affected in their behavior on plants led to the identification of different types of genes involved in plant-pathogen interactions. The genes required for both the expression of disease symptoms on host plants and the development of the hypersensitive reaction on non-host plants have been designated hrp for hypersensitive reaction and pathogenicity (41).The first P. syringae pv. syringae hrp mutant was obtained by TnS mutagenesis of a streptomycin-resistant derivative of strain R32 (2). Complementation of the mutant phenotype and transposon mutagenesis allowed delimitation of the hrpM locus to a length of 3.9 kb (29), while sequence analysis revealed two open reading frames, ORF1 and ORF2 (31). The gene for ORF2 was designated hrpM. The hrpM gene product was predicted to be an 83-kDa protein spanning the cell membrane. Its function was not elucidated; this protein is not required for growth in minimal medium but is required for growth of bacteria in planta (28).Recently, Loubens and coworkers (20) have discovered considerable homology (69% identical nucleotides out of 2,816) between the P. syringae pv. syringae hrpM locus and the Escherichia coli mdoGH operon. In E. coli, both genes are required for the synthesis of periplasmic glucans (17). The mdoG gene product is a 56-kDa periplasmic protein whose function remains to be determined, while the mdoH gene product, known to be necessary for glucosyl transferase activity, is a 97-kDa protein spanning the cell membrane (20 ...

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Periplasmic glucans of Pseudomonas syringae pv. syringae

1994

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“…These cell surface carbohydrates include extracellular polysaccharides, capsular polysaccharides, lipopolysaccharides, and periplasmic glucans. Recent studies have demonstrated that Agrobacterium and Rhizobium species synthesize neutral and anionic periplasmic glucans of similar structure (2,5,16,17,20,21,23). In both genera, these periplasmic glucans are composed of a cyclic beta-1,2-glucan backbone containing 17 to 24 glucose residues.…”

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Cell-associated oligosaccharides of Bradyrhizobium spp

et al. 1990

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We report the initial characterization of the cell-associated oligosaccharides produced by four Bradyrhizobium strains: Bradyrhizobiumjaponicum USDA 110, USDA 94, and ATCC 10324 and Bradyrhizobium sp. strain 32H1. The cell-associated oligosaccharides of these strains were found to be composed solely of glucose and were predominantly smaller than the cyclic beta-1,2-glucans produced by Agrobacterium and Rhizobium species. Linkage studies and nuclear magnetic resonance analyses demonstrated that the bradyrhizobial glucans are linked primarily by beta-1,6 and beta-1,3 glycosidic bonds. Thus, the bradyrhizobia appear to synthesize cell-associated oligosaccharides of structural character substantially different from that of the cyclic beta-1,2-glucans produced by Agrobacterium and Rhizobium species.Bacterial genera in the family Rhizobiaceae are distinguished by their ability to infect higher plants. In the case of Rhizobium and Bradyrhizobium species, this infection process leads to a beneficial symbiotic relationship in which nitrogen-fixing nodules develop on the roots of leguminous plants. Plant infection by Agrobacterium species, however, results in the production of tumors on susceptible plant hosts. The cell surface carbohydrates of all three genera are believed to play important roles in the plant infection process. These cell surface carbohydrates include extracellular polysaccharides, capsular polysaccharides, lipopolysaccharides, and periplasmic glucans. Recent studies have demonstrated that Agrobacterium and Rhizobium species synthesize neutral and anionic periplasmic glucans of similar structure (2,5,16,17,20,21,23). In both genera, these periplasmic glucans are composed of a cyclic beta-1,2-glucan backbone containing 17 to 24 glucose residues. In Agrobacterium tumefaciens, approximately 50% of the total periplasmic cyclic beta-1,2-glucans are present as neutral, unsubstituted molecules (22). The remaining molecules are substituted with one or more phosphoglycerol moieties (23). In Rhizobium meliloti, as much as 90% of the periplasmic cyclic beta-1,2-glucans may be substituted with anionic moieties (21). As in the cyclic glucans of A. tumefaciens, the predominant anionic substituent present on the cyclic beta-1,2-glucans of R. meliloti 1021 is phosphoglycerol (21).Recently, studies by Nester and co-workers (9, 26) and Geremia and co-workers (11) have provided evidence for a role for cyclic beta-1,2-glucans in the plant infection process. Specifically, cyclic beta-1,2-glucans have been implicated in the attachment of the bacterial cell to the plant host. Although there have been previous reports that at least two strains of Bradyrhizobium japonicum are capable of synthesizing neutral beta-1,2-linked glucans (1, 4), very little characterization of the cell-associated oligosaccharides of Bradyrhizobium species has been performed to date. We now report the results of our analyses of the cell-associated oligosaccharides of four Bradyrhizobium strains.(A preliminary report of this work has appeared previ-* Cor...

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“…The cyclic glucans are heterogeneous in size, ranging from 17 to 40 glucosyl residues (9,10). Bacterial strains such as the Agrobacterium, Sinorhizobium, Mesorhizobium and Brucella species produce periplasmic cyclic β-glucans belonging to Family II (9,11,12). PGs belonging to Family III are cyclic glucans linked by β-(1,3) and β-(1,6) glycosidic bonds with DPs that range from 10 to 13 glucose units that are produced by Bradyrhizobium spp.…”

Section: Classification Of Pgsmentioning

confidence: 99%