Purine auxotrophs of various Rhizobium species are symbiotically defective, usually unable to initiate or complete the infection process. Earlier studies demonstrated that, in the Rhizobium etli-bean symbiosis, infection by purine auxotrophs is partially restored by supplementation of the plant medium with 5-amino-imidazole-4-carboxamide (AICA) riboside, the unphosphorylated form of the purine ...

Research in the field of Rhizobium-legume symbiosis faces a new challenge: integrate the wealth of information generated by genomic projects. The goal: apprehend the complexity of the molecular mechanisms involved in symbiotic associations. At the time of writing, the genomes of three micro-symbionts (Bradyrhizobium japonicum, Mesorhizobium loti and Sinorhizobium meliloti) have been sequenced, ...

The prominent feature of rhizobia is their molecular dialogue with plant hosts. Such interaction is enabled by the presence of a series of symbiotic genes encoding for the synthesis and export of signals triggering organogenetic and physiological responses in the plant. The genome of the Rhizobium sullae type strain IS123T nodulating the legume Hedysarum coronarium, was sequenced and resulted i...

The structure of the lipid A from Rhizobium etli and Rhizobium leguminosarum lipopolysaccharides (LPSs) lacks phosphate and contains a galacturonosyl residue at its 4' position, an acylated 2-aminogluconate in place of the proximal glucosamine, and a very long chain omega-1 hydroxy fatty acid, 27-hydroxyoctacosanoic acid (27OHC28:0). The 27OHC28:0 moiety is common in lipid A's among members of ...

A quantitative method was developed to measure the binding of fluorescent-labeled lentil (Lens esculenta Moench), pea (Pisum sativum L.), broad bean (Vicia faba L.), and jackbean (Canavalia ensiformis L., DC.) lectins to various Rhizobium strains. Lentil lectin bound to three of the five Rhizobium leguminosarum strains tested. The number of lentil lectin molecules bound per R. leguminosarum 128...

Centro de Ciencias Genómicas (B.N.-F., L.P.I., A.L., S.I.F., M.R., S.P., L.G., G.H.), Laboratorio Nacional de Microscopía Avanzada (X.A.-A.), and Departamento de Biología Molecular de Plantas (J.L.R.), Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, Mexico; and Laboratorio de Genómica Funcional de Leguminosas, Facultad de Estudios Superiores Iztac...

Habitat fragmentation affects the biodiversity and function of aboveground organisms in natural ecosystems but has not been studied for effects on belowground species. In this paper, we consider the diversity of the rhizobia associated with the indigenous legume Dalea purpurea in 3 residual prairie areas in Minnesota and Iowa. Using Dalea purpurea as a trap host, 218 rhizobia were recovered fro...

The complete nucleotide sequence of the nodS gene from the bean-nodulating Rhizobium etli, presumably encoding a methyltransferase, was determined. A phylogenetic analysis of five different NodS proteins from three genera of Gram- soil bacteria, Azorhizobium, Bradyrhizobium and Rhizobium, was performed.