The Role of Microbial Surface Polysaccharides in the Rhizobium-Legume Interaction

Niehaus, Karsten; Becker, Anke

doi:10.1007/978-1-4899-1707-2_3

Cited by 55 publications

(49 citation statements)

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“…To study the competitive ability of the strains, we employed S. meliloti strain L753, which can be easily detected inside root nodules because of the expression of an eglC-gusA fusion. 2 Results of two coinoculation experiments, where 1021 and L994 were tested against L753, showed that L994 was a weaker competitor than 1021 (Table III). Taken together, the obtained results show that the acpXL mutation caused attenuation of the outer membrane permeability barrier and quantitatively impaired symbiotic performance of S. meliloti.…”

Section: Lps Of Mutant L994 Showed the Same Immunological Properties mentioning

confidence: 99%

“…Bacteria induce the formation of nodules on roots of their host plants and colonize the root tissue as intracellular nitrogen-fixing bacteroids (1). Rhizobial cell surface polysaccharides play an important role during this process (2). LPS 1 constitutes an integral part of the outer cell membrane of Gram-negative bacteria.…”

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confidence: 99%

“…The role of bacterial LPS in symbiotic interactions with plants seems to be profoundly different from its role in pathogenic interactions with animals. There are several lines of evidence that LPS of rhizobia may suppress host defense responses in plant cells and promote symbiotic interaction (2,17,18). Studies with rhizobial mutants producing modified lipid A may shed more light on mechanisms of LPS interaction with plant cells.…”

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confidence: 99%

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Sinorhizobium meliloti acpXL Mutant Lacks the C28 Hydroxylated Fatty Acid Moiety of Lipid A and Does Not Express a Slow Migrating Form of Lipopolysaccharide

Sharypova

Niehaus

Scheidle

et al. 2003

Journal of Biological Chemistry

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Lipid A is the hydrophobic anchor of lipopolysaccharide (LPS) in the outer membrane of Gram-negative bacteria. Lipid A of all Rhizobiaceae is acylated with a long fatty acid chain, 27-hydroxyoctacosanoic acid. Biosynthesis of this long acyl substitution requires a special acyl carrier protein, AcpXL, which serves as a donor of C28 (-1)-hydroxylated fatty acid for acylation of rhizobial lipid A (Brozek, K.A., Carlson, R.W., and Raetz, C. R. (1996) J. Biol. Chem. 271, 32126 -32136). To determine the biological function of the C28 acylation of lipid A, we constructed an acpXL mutant of Sinorhizobium meliloti strain 1021. Gas-liquid chromatography and mass spectrometry analysis of the fatty acid composition showed that the acpXL mutation indeed blocked C28 acylation of lipid A. SDS-PAGE analysis of acpXL mutant LPS revealed only a fast migrating band, rough LPS, whereas the parental strain 1021 manifested both rough and smooth LPS. Regardless of this, the LPS of parental and mutant strains had a similar sugar composition and exposed the same antigenic epitopes, implying that different electrophoretic profiles might account for different aggregation properties of LPS molecules with and without a long acyl chain. The acpXL mutant of strain 1021 displayed sensitivity to deoxycholate, delayed nodulation of Medicago sativa, and a reduced competitive ability. However, nodules elicited by this mutant on roots of M. sativa and Medicago truncatula had a normal morphology and fixed nitrogen. Thus, the C28 fatty acid moiety of lipid A is not crucial, but it is beneficial for establishing an effective symbiosis with host plants. acpXL lies upstream from a cluster of five genes, including msbB (lpxXL), which might be also involved in biosynthesis and transfer of the C28 fatty acid to the lipid A precursor.

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Section: Lps Of Mutant L994 Showed the Same Immunological Properties mentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Sinorhizobium meliloti acpXL Mutant Lacks the C28 Hydroxylated Fatty Acid Moiety of Lipid A and Does Not Express a Slow Migrating Form of Lipopolysaccharide

Sharypova

Niehaus

Scheidle

et al. 2003

Journal of Biological Chemistry

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“…A genetic approach has led recently to the cloning of a receptor kinase, with a novel extracellular domain, important for Nod factor responses (Endre et al, 2002;Stracke et al, 2002), but its dual role in establishment of a symbiosis with mycorrhizal fungi suggests that it may not be involved directly in Nod factor binding (Kistner and Parniske, 2002). The other type of saccharidic signals involved in the symbiosis are the rhizobial cell surface polysaccharides (exo-, lipo-, and capsular polysaccharides) and include small molecules derived from them that may play a signaling role (Niehaus and Becker, 1998). Generally, these saccharides appear to play a major role in infection rather than nodule organogenesis (Niehaus and Becker, 1998;Hirsch, 1999).…”

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confidence: 99%

“…The other type of saccharidic signals involved in the symbiosis are the rhizobial cell surface polysaccharides (exo-, lipo-, and capsular polysaccharides) and include small molecules derived from them that may play a signaling role (Niehaus and Becker, 1998). Generally, these saccharides appear to play a major role in infection rather than nodule organogenesis (Niehaus and Becker, 1998;Hirsch, 1999).…”

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Characterization of Four Lectin-Like Receptor Kinases Expressed in Roots of Medicago truncatula. Structure, Location, Regulation of Expression, and Potential Role in the Symbiosis with Sinorhizobium meliloti

et al. 2003

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To study the role of LecRK (lectin-like receptor kinase) genes in the legume-rhizobia symbiosis, we have characterized the four Medicago truncatula Gaernt. LecRK genes that are most highly expressed in roots. Three of these genes, MtLecRK7;1, MtLecRK7;2, and MtLecRK7;3, encode proteins most closely related to the Class A LecRKs of Arabidopsis, whereas the protein encoded by the fourth gene, MtLecRK1;1, is most similar to a Class B Arabidopsis LecRK. All four genes show a strongly enhanced root expression, and detailed studies on MtLecRK1;1 and MtLecRK7;2 revealed that the levels of their mRNAs are increased by nitrogen starvation and transiently repressed after either rhizobial inoculation or addition of lipochitooligosaccharidic Nod factors. Studies of the MtLecRK1;1 and MtLecRK7;2 proteins, using green fluorescent protein fusions in transgenic M. truncatula roots, revealed that they are located in the plasma membrane and that their central transmembrane-spanning helix is required for correct sorting. Moreover, their lectin-like domains appear to be highly glycosylated. Of the four proteins, only MtLecRK1;1 shows a high conservation of key residues implicated in monosaccharide binding, and molecular modeling revealed that this protein may be capable of interacting with Nod factors. However, no increase in Nod factor binding was found in roots overexpressing a fusion in which the kinase domain of this protein had been replaced with green fluorescent protein. Roots expressing this fusion protein however showed an increase in nodule number, suggesting that expression of MtLecRK1;1 influences nodulation. The potential role of LecRKs in the legumerhizobia symbiosis is discussed.The lectin-like receptor kinases (LecRKs) are a class of proteins originally described from Arabidopsis (Hervé et al., 1996). They have a structure similar to other plant receptor-like kinases (RLKs; Shiu and Bleecker, 2001;Cock et al., 2002) with an N-terminal targeting signal, a presumably extracellular domain, a single transmembrane (TM)-spanning helix, and a cytosolic kinase domain. The Arabidopsis genome contains over 610 RLKs that have been shown to be monophylogenetic with respect to the kinase domain and most closely related to the fruitfly (Drosophila melanogaster) Pelle and related animal cytoplasmic kinases (Shiu and Bleecker, 2001). In cases in which they have been tested, these kinases have been shown to have specificity for phosphorylation on Ser/Thr residues (Shiu and Bleecker, 2001).The plant RLKs can be grouped into more than 21 structural classes based on their extracellular domains (Shiu and Bleecker, 2001). The LecRKs represent one such class in which the extracellular domain is related to legume lectins. The Arabidopsis genome contains at least 42 LecRK sequences that have been grouped into three classes (A-C) plus an additional nine sequences of related soluble lectins (Barre et al., 2002). Searches in plant databases reveal that LecRK genes are widespread in higher plants, but apart from Arabidopsis (Hervé et al., 1996,...

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Lectin Receptor like Kinase

Passricha

Saifi

Negi³

et al. 2020

Protein Kinases and Stress Signaling in Plants

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The Role of Microbial Surface Polysaccharides in the Rhizobium-Legume Interaction

Cited by 55 publications

References 203 publications

Sinorhizobium meliloti acpXL Mutant Lacks the C28 Hydroxylated Fatty Acid Moiety of Lipid A and Does Not Express a Slow Migrating Form of Lipopolysaccharide

Sinorhizobium meliloti acpXL Mutant Lacks the C28 Hydroxylated Fatty Acid Moiety of Lipid A and Does Not Express a Slow Migrating Form of Lipopolysaccharide

Characterization of Four Lectin-Like Receptor Kinases Expressed in Roots of Medicago truncatula. Structure, Location, Regulation of Expression, and Potential Role in the Symbiosis with Sinorhizobium meliloti

Lectin Receptor like Kinase

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