Lotus corniculatus Nodulation Specificity Is Changed by the Presence of a Soybean Lectin Gene

Rhijn, Pieternel van; Goldberg, Robert B.; Hirsch, Ann M.

doi:10.2307/3870637

Cited by 18 publications

(26 citation statements)

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“…Previous attempts to implicate lectins in this symbiosis have been focused on the legume seed lectins (30,31), which have not been reported to bind Nod factors. As a Nod factor-binding protein, LNP could possibly function in Nod factor transport, as a host/strain specific receptor, as a second, less stringent receptor postulated for this process (32), or even perhaps participate in events leading to a modification of the ligand.…”

Section: Discussionmentioning

confidence: 99%

A nod factor binding lectin with apyrase activity from legume roots

Kalsi

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

151

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A lectin isolated from the roots of the legume, Dolichos biflorus, binds to Nod factors produced by rhizobial strains that nodulate this plant and has a deduced amino acid sequence with no significant homology to any lectin reported to date. This lectin also is an enzyme that catalyzes the hydrolysis of phosphoanhydride bonds of nucleoside di-and triphosphates; the enzyme activity is increased in the presence of carbohydrate ligands. This lectin-nucleotide phosphohydrolase (LNP) has a substrate specificity characteristic of the apyrase category of phosphohydrolases, and its sequence contains four motifs characteristic of this category of enzymes. LNP is present on the surface of the root hairs, and treatment of roots with antiserum to LNP inhibits their ability to undergo root hair deformation and to form nodules on exposure to rhizobia. These properties suggest that this protein may play a role in the rhizobium-legume symbiosis and/or in a related carbohydrate recognition event endogenous to the plant.Oligosaccharide signaling events play important roles in the regulation of plant development, defense, and other interactions of plants with the environment (1-4). The establishment of the nitrogen-fixing symbiotic relationship between rhizobia and leguminous plants depends on such a signaling process. The rhizobia produce lipochitooligosaccharidic signals, called Nod factors, that elicit the differentiation of a new organ, the nodule, in the root cortex. The rhizobia bind to and invade the root hairs, where they proceed to the emerging nodule within infection threads produced by the plant (5). Both the initiation of nodule formation and rhizobial entry are host-strainspecific; this specificity is determined by the type of Nod factor produced by a particular rhizobial strain and by the ability of a leguminous species to recognize that signal.All Nod factors consist of a short, typically tetrapentameric, chitin oligosaccharidic backbone that is N-acylated at the nonreducing end, usually with a common fatty acid, such as cis-vaccenic acid. The Nod factors differ from one another in length of this backbone and the type of substituents that decorate it; these modifications determine the strain specificity of the rhizobium and depend on the set of nodulation genes possessed by that rhizobial strain (4). A related set of signals are the chitin oligosaccharides, themselves, that have been found to elicit defense responses in a wide variety of plants (for review, see ref.3).Although the structures of many of these chitooligosaccharides have been characterized, little is known about the plant proteins that bind these signals, whether as receptors for signal transduction or as binding proteins with other functions. High-affinity binding sites for chitin fragments have been found on membranous fractions prepared from tomato (7) and rice (8) suspension-cultured cells, and a 70-kDa protein that binds to chitin fragments was isolated from the rice membranes (9). Particulate fractions from roots of the legume, Medicago t...

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Section: Discussionmentioning

confidence: 99%

A nod factor binding lectin with apyrase activity from legume roots

Kalsi

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

151

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“…Introduced lectins were localized at root hair tips, and mutation in the sugar-binding site aborted nodulation (van Eijsden et a/. 1995, van Rhijn et a/. 1998.…”

Section: Earliest Events At Root Hairs: How Do Legumesmentioning

confidence: 99%

Nodule Organogenesis in Lotus japonicus

et al. 2000

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Interactions between legumes and rhizobia are one of the best-characterized symbioses. Legumes develop nodules in response to rhizobia infection. Nod factors are essential for the recognition by legumes of rhizobia. Nodule primordia arise from root cortex, where vacuolated cells are redifferentiated. Rhizobia infect legumes via root hairs, penetrating via infection threads provided by the plant. After their release from infection threads into plant cells, rhizobia fix aerial nitrogen by differentiating to bacteroids. The mechanism of nodule organogenesis is poorly understood. This is partly because there has been l i l e molecular analysis on nodulation mutants. Recent advances in the use of model legumes, however, have enabled one to characterize nodulation mutants by molecular genetics. In this review, we will focus on the early steps of nodule organogenesis in relation to the analysis of a model legume, Lotus japonicus.

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“…Although the role of lectins in the rhizobial-leguminous plant symbioses is still questioned (Kijne 1992;Hirsch et al 1995;van Rhijn et al 1998), SBL binding is a useful tool in studying rhizobial EPSs and surface polysaccharides and their roles in the infection and symbiosis of legumes.…”

Section: Introductionmentioning

confidence: 99%

Altered exopolysaccharides of Bradyrhizobium japonicum mutants correlate with impaired soybean lectin binding, but not with effective nodule formation

Karr

Liang

Reuhs

et al. 2000

Planta

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The exact mechanism(s) of infection and symbiotic development between rhizobia and legumes is not yet known, but changes in rhizobial exopolysaccharides (EPSs) affect both infection and nodule development of the legume host. Early events in the symbiotic process between Bradyrhizobium japonicum and soybean (Glycine max [L.] Merr.) were studied using two mutants, defective in soybean lectin (SBL) binding, which had been generated from B. japonicum 2143 (USDA 3I-1b-143 derivative) by Tn5 mutagenesis. In addition to their SBL-binding deficiency, these mutants produced less EPS than the parental strain. The composition of EPS varied with the genotype and with the carbon source used for growth. When grown on arabinose, gluconate, or mannitol, the wild-type parental strain, B. japonicum 2143, produced EPS typical of DNA homology group I Bradyrhizobium, designated EPS I. When grown on malate, strain 2143 produced a different EPS composed only of galactose and its acetylated derivative and designated EPS II. Mutant 1252 produced EPS II when grown on arabinose or malate, but when grown on gluconate or mannitol, mutant 1252 produced a different EPS comprised of glucose, galactose, xylose and glucuronic acid (1:5:1:1) and designated EPS III. Mutant 1251, grown on any of these carbon sources, produced EPS III. The EPS of strain 2143 and mutant 1252 contained SBL-binding polysaccharide. The amount of the SBL-binding polysaccharide produced by mutant 1252 varied with the carbon source used for growth. The capsular polysaccharide (CPS) produced by strain 2143 during growth on arabinose, gluconate or mannitol, showed a high level of SBL binding, whereas CPS produced during growth of strain 2143 on malate showed a low level of SBL binding. However, the change in EPS composition and SBL binding of strain 2143 grown on malate did not affect the wild-type nodulation and nitrogen fixation phenotype of 2143. Mutant 1251, which produced EPS III, nodulated 2 d later than parental strain 2143, but formed effective, nitrogen-fixing tap root nodules. Mutant 1252, which produced either EPS II or III, however nodulated 5-6 d later and formed few and ineffective tap root nodules. Restoration of EPS I production in mutant 1252 correlated with restored SBL binding, but not with wild-type nodulation and nitrogen fixation.

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Lotus corniculatus Nodulation Specificity Is Changed by the Presence of a Soybean Lectin Gene

Cited by 18 publications

References 0 publications

A nod factor binding lectin with apyrase activity from legume roots

A nod factor binding lectin with apyrase activity from legume roots

Nodule Organogenesis in Lotus japonicus

Altered exopolysaccharides of Bradyrhizobium japonicum mutants correlate with impaired soybean lectin binding, but not with effective nodule formation

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