The Wall of Rhizobium leguminosarum in Bacteroid and Free-living Forms

Brussel, A. A. N. Van; Planqué, K.; Quispel, A.

doi:10.1099/00221287-101-1-51

Cited by 107 publications

(58 citation statements)

References 25 publications

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“…Unless otherwise indicated, the ,B-galactosidase values in the tables are expressed as Miller units (21) induced by 30-fold-diluted root exudate and corrected for the background level of the indicator strain, which was 300 to 400 U. Culture supernatant fluids of Rhizobium cells to be tested for the presence of symbiotic signals were taken from cells grown in B medium (39), which, if appropriate, was supplemented with the nod gene inducer naringenin (1 ,uM). The fluids were tested after centrifugation for 10 min' at 6,000 x g and pasteurization for 10 min at 800C.…”

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A biovar-specific signal of Rhizobium leguminosarum bv. viciae induces increased nodulation gene-inducing activity in root exudate of Vicia sativa subsp. nigra

et al. 1990

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Flavonoids in root exudate of leguminous plants activate the transcription of Rhizobium genes involved in the formation of root nodules (nod genes). We report that inoculation with the homologous symbiont R. kguminosarum bv. viciae results in an increased nod gene-inducing activity (Ini) in root exudate of V. sativa subsp. nigra, whereas inoculation with heterologous Rhizobium strains results in exudates with nod geneinducing activity comparable to that of uninfected plants. Ini can be demonstrated by using either of the isogenic indicator strains containing an inducible nod promoter fused to the Escherichia coli lacZ reporter gene and the regulatory nodD gene of R. leguminosarum bv. viciae, R. leguminosarum bv. trifolii, or R. meliloti. The presence of genes nodDABCEL of R. leguminosarum bv. viciae appeared to be essential for induction of Ini. Mutation of the genes nodI and nodJ causes a delay of Ini, whereas gene nodF appears to be required for both the timely appearance and the maximum level of Ini activity. The nodE gene is responsible for the biovar specificity of induction of Ini by Rhizobium spp. Ini is caused by a soluble heat-stable factor of rhizobial origin. This Rhizobium-produced Ini factor has an apparent molecular weight between 1,000 and 10,000 and does not originate from flavonoid precursors.Induction by Rhizobium bacteria of symbiotic nitrogenfixing root nodules on leguminous plants is a host-specific process; e.g., R. leguminosarum bv. viciae nodulates common vetch, pea, sweet pea, and lentil but not clover or bean, whereas R. leguminosarum bv. trifolii nodulates only clover. Many genes required for root nodule formation (nod genes) by Rhizobium species, including those of R. leguminosarum, are located on a symbiosis (Sym) plasmid. In R. leguminosarum three types of nod genes have been distinguished: (i) a regulatory gene, nodD; (ii) the common nod genes, nodAB-CIJ; and (iii) the genes nodFELMNTO, of which the nodE gene is a host-specific gene which determines whether R. leguminosarum is able to nodulate Vicia or Trifolium plants (3-5, 14, 19, 27, 33). The NodD protein, which is required for activation of the other, inducible nod genes, is only active together with signal molecules, identified as flavonoids, which are exuded by the host plant roots (9,22,25,46 (22,25,46). However, in nature root exudate is not sterile, and we therefore extended our studies to exudate of plants that had been inoculated with Rhizobium spp. (coculture exudate). In this paper, we report that inoculation of Vicia sativa subsp. nigra plants with R. leguminosarum bv. viciae results in significantly increased nod gene-inducing activity (Ini) in coculture exudate. We show that this effect is induced by a biovar-specific extracellular signal of R. leguminosarum bv. viciae. The production of this signal, which is not a flavonoid, requires induction of specific nod genes. MATERIALS AND METHODSBacterial strains, plasmids, and growth conditions. Rhizobium strains and plasmids used in this study are listed in Table 1. Plas...

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“…Supernatant fluids of cultures of strain RBL5561 pMP604 in B medium (39) were used as a source of the Ini factor. Heat stability was tested after incubation for 10 min at 1200C.…”

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confidence: 99%

A biovar-specific signal of Rhizobium leguminosarum bv. viciae induces increased nodulation gene-inducing activity in root exudate of Vicia sativa subsp. nigra

et al. 1990

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“…- [17] при + 28 °C и интенсивном перемешивании 220 об/мин в присутствии 10 мкМ нарингенина (индуктор). Клет-ки осаждали 15 мин при 4000 g, затем супернатант ин-кубировали с бутанолом в течение 1 часа при пере-мешивании 220 об/мин, бутанольную фазу отбирали и выпаривали.…”

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Studying the biochemical function of the pea receptor-like kinases sym10, sym37 and k1, required for the legume-rhizobia symbiosis development

Долгих

Анатольевна²,

Kirienko

et al. 2017

Ecological genetics

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Background. Rhizobial Nod factors (NFs), the key regulators of legume-rhizobia symbiosis, act in low concentrations and their biological activity depends on structural features, that suggests the presence of specific receptors in plants. Putative receptors, LysM-receptor-like kinases (LysM-RLKs), were found in model legumes L. japonicus and M. truncatula. However, binding capacity with NFs was only studied for L. japonicus LysM-RLKs. In pea a few candidates for NF receptors like Sym10, Sym37 and K1 were found. Analysis of mutants revealed the importance of these proteins for symbiosis development. However, the biochemical function of these receptors has not been studied. Materials and methods. Sequences encoding extracellular domains (ECDs) of LysM-RLKs Sym10, Sym37, and K1 were cloned in the pRSETa vector. Constructs were introduced in E. coli strain C41 to produce proteins with His6 residues on either the amino or carboxyl terminus. Protein purification was carried out using metal chelate affinity chromatography. The binding capacity with ligand was evaluated using ProteonXPR36 biosensor. Results. To study binding capacity with NFs, we have developed approaches for the synthesis of LysM-RLK Sym10, Sym37 and K1 in soluble form in heterologous system. The high level of protein synthesis was achieved at +28 °C using 0,5 mM IPTG in 2-16 hours. Analysis of binding capacity of ECDs with NFs revealed the low affinity using the surface plasmon resonance. Conclusion. The possibility of recombinant receptor synthesis in soluble state in E. coli at high level was demonstrated. Analysis of binding capacity with NFs showed the potential interaction, but with low affinity.

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“…Several reports have indicated that the amount of LPS in the outer membrane decreases in a cell (Van Brussel et al 1977) and that the composition of the membrane changes during the differentiation from free-living bacterium to bacteroid (Brewin et al 1986;Sindhu et al 1990;VandenBosch et al 1989). Goosen-de Roo et al (1991) demonstrated by electron microscopy with monoclonal antibody of O-antigens of LPS of Rhizobium leguminosarum bv.…”

Section: Discussionmentioning

confidence: 99%

Concomitant inhibition of nitrogen fixation and N-Phenyl-¹-Naphthylamine uptake activity of bacteroids of aBradyrhizohium japonicumstrain by nitrate

Ozawa¹,

Kato²,

Matsunami³

1995

Soil Science and Plant Nutrition

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The Wall of Rhizobium leguminosarum in Bacteroid and Free-living Forms

Cited by 107 publications

References 25 publications

A biovar-specific signal of Rhizobium leguminosarum bv. viciae induces increased nodulation gene-inducing activity in root exudate of Vicia sativa subsp. nigra

A biovar-specific signal of Rhizobium leguminosarum bv. viciae induces increased nodulation gene-inducing activity in root exudate of Vicia sativa subsp. nigra

Studying the biochemical function of the pea receptor-like kinases sym10, sym37 and k1, required for the legume-rhizobia symbiosis development

Concomitant inhibition of nitrogen fixation and N-Phenyl-¹-Naphthylamine uptake activity of bacteroids of aBradyrhizohium japonicumstrain by nitrate

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The Wall of Rhizobium leguminosarum in Bacteroid and Free-living Forms

Cited by 107 publications

References 25 publications

A biovar-specific signal of Rhizobium leguminosarum bv. viciae induces increased nodulation gene-inducing activity in root exudate of Vicia sativa subsp. nigra

A biovar-specific signal of Rhizobium leguminosarum bv. viciae induces increased nodulation gene-inducing activity in root exudate of Vicia sativa subsp. nigra

Studying the biochemical function of the pea receptor-like kinases sym10, sym37 and k1, required for the legume-rhizobia symbiosis development

Concomitant inhibition of nitrogen fixation and N-Phenyl-1-Naphthylamine uptake activity of bacteroids of aBradyrhizohium japonicumstrain by nitrate

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Concomitant inhibition of nitrogen fixation and N-Phenyl-¹-Naphthylamine uptake activity of bacteroids of aBradyrhizohium japonicumstrain by nitrate