Rhizobium leguminosarum: A species of gram-negative, aerobic bacteria that is found in soil and which causes formation of root nodules on some, but not all, types of field pea, lentil, kidney bean, and clover.Rhizobium: A genus of gram-negative, aerobic, rod-shaped bacteria that activate PLANT ROOT NODULATION in leguminous plants. Members of this genus are nitrogen-fixing and common soil inhabitants.Fabaceae: The large family of plants characterized by pods. Some are edible and some cause LATHYRISM or FAVISM and other forms of poisoning. Other species yield useful materials like gums from ACACIA and various LECTINS like PHYTOHEMAGGLUTININS from PHASEOLUS. Many of them harbor NITROGEN FIXATION bacteria on their roots. Many but not all species of "beans" belong to this family.Nitrogen Fixation: The process in certain BACTERIA; FUNGI; and CYANOBACTERIA converting free atmospheric NITROGEN to biologically usable forms of nitrogen, such as AMMONIA; NITRATES; and amino compounds.Symbiosis: The relationship between two different species of organisms that are interdependent; each gains benefits from the other or a relationship between different species where both of the organisms in question benefit from the presence of the other.Peas: A variable annual leguminous vine (Pisum sativum) that is cultivated for its rounded smooth or wrinkled edible protein-rich seeds, the seed of the pea, and the immature pods with their included seeds. (From Webster's New Collegiate Dictionary, 1973)Plants, Medicinal: Plants whose roots, leaves, seeds, bark, or other constituent parts possess therapeutic, tonic, purgative, curative or other pharmacologic attributes, when administered to man or animals.Vicia sativa: A plant species of the genus VICIA, family FABACEAE. The seed is used for food and contains THIOCYANATES such as prunasin, cyanoalanine, cyanogen, and vicine.Rhizobium etli: A species of gram-negative bacteria and nitrogen innoculant of PHASEOLUS VULGARIS.Vicia: A plant genus of the family FABACEAE that is widely used as ground cover and forage and known for the edible beans, VICIA FABA.Trifolium: A plant genus of the family FABACEAE.Genes, Bacterial: The functional hereditary units of BACTERIA.Bacterial Proteins: Proteins found in any species of bacterium.Sinorhizobium meliloti: A species of gram-negative, aerobic bacteria that causes formation of root nodules on some, but not all, types of sweet clover, MEDICAGO SATIVA, and fenugreek.Root Nodules, Plant: Knobbed structures formed from and attached to plant roots, especially of LEGUMES, which result from symbiotic infection by nitrogen fixing bacteria such as RHIZOBIUM or FRANKIA. Root nodules are structures related to MYCORRHIZAE formed by symbiotic associations with fungi.Rhizobiaceae: A family of gram-negative bacteria which are saprophytes, symbionts, or plant pathogens.Medicago: A plant genus of the family FABACEAE. It is distinct from Sweet Clover (MELILOTUS), from Bush Clover (LESPEDEZA), and from Red Clover (TRIFOLIUM).Cosmids: Plasmids containing at least one cos (cohesive-end site) of PHAGE LAMBDA. They are used as cloning vehicles.Lens Plant: A plant genus of the FABACEAE family known for the seeds used as food.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Rhizobium tropici: A species of gram-negative bacteria and an nitrogen inoculum that displays a high intrinsic tolerance to acidity.Plant Root Nodulation: The formation of a nitrogen-fixing cell mass on PLANT ROOTS following symbiotic infection by nitrogen-fixing bacteria such as RHIZOBIUM or FRANKIA.Hydrogenase: An enzyme found in bacteria. It catalyzes the reduction of FERREDOXIN and other substances in the presence of molecular hydrogen and is involved in the electron transport of bacterial photosynthesis.Plasmids: Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.Gene Expression Regulation, Bacterial: Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.Lipid A: Lipid A is the biologically active component of lipopolysaccharides. It shows strong endotoxic activity and exhibits immunogenic properties.Plant Roots: The usually underground portions of a plant that serve as support, store food, and through which water and mineral nutrients enter the plant. (From American Heritage Dictionary, 1982; Concise Dictionary of Biology, 1990)DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Polysaccharides, Bacterial: Polysaccharides found in bacteria and in capsules thereof.Flavanones: A group of FLAVONOIDS characterized with a 4-ketone.Sinorhizobium: A genus of gram-negative, aerobic, nonsporeforming rods which usually contain granules of poly-beta-hydroxybutyrate. (From Bergey's Manual of Determinative Bacteriology, 9th ed)Medicago sativa: A plant species of the family FABACEAE widely cultivated for ANIMAL FEED.Dicarboxylic AcidsMutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Genetic Complementation Test: A test used to determine whether or not complementation (compensation in the form of dominance) will occur in a cell with a given mutant phenotype when another mutant genome, encoding the same mutant phenotype, is introduced into that cell.Dicarboxylic Acid Transporters: A family of organic anion transporters that specifically transport DICARBOXYLIC ACIDS such as alpha-ketoglutaric acid across cellular membranes.Bradyrhizobium: A genus of gram-negative, aerobic, rod-shaped bacteria usually containing granules of poly-beta-hydroxybutyrate. They characteristically invade the root hairs of leguminous plants and act as intracellular symbionts.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Phaseolus: A plant genus in the family FABACEAE which is the source of edible beans and the lectin PHYTOHEMAGGLUTININS.Sugar AcidsMutagenesis, Insertional: Mutagenesis where the mutation is caused by the introduction of foreign DNA sequences into a gene or extragenic sequence. This may occur spontaneously in vivo or be experimentally induced in vivo or in vitro. Proviral DNA insertions into or adjacent to a cellular proto-oncogene can interrupt GENETIC TRANSLATION of the coding sequences or interfere with recognition of regulatory elements and cause unregulated expression of the proto-oncogene resulting in tumor formation.Nitrogenase: An enzyme system that catalyzes the fixing of nitrogen in soil bacteria and blue-green algae (CYANOBACTERIA). EC Sequence: The sequence of carbohydrates within POLYSACCHARIDES; GLYCOPROTEINS; and GLYCOLIPIDS.Operon: In bacteria, a group of metabolically related genes, with a common promoter, whose transcription into a single polycistronic MESSENGER RNA is under the control of an OPERATOR REGION.Fructokinases: A class of enzymes that catalyzes the phosphorylation of fructose in the presence of ATP. EC 2.7.1.-.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Plants: Multicellular, eukaryotic life forms of kingdom Plantae (sensu lato), comprising the VIRIDIPLANTAE; RHODOPHYTA; and GLAUCOPHYTA; all of which acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Plant Exudates: Substances released by PLANTS such as PLANT GUMS and PLANT RESINS.AcetyleneHydroxy Acids: Organic compounds containing both the hydroxyl and carboxyl radicals.Lipopolysaccharides: Lipid-containing polysaccharides which are endotoxins and important group-specific antigens. They are often derived from the cell wall of gram-negative bacteria and induce immunoglobulin secretion. The lipopolysaccharide molecule consists of three parts: LIPID A, core polysaccharide, and O-specific chains (O ANTIGENS). When derived from Escherichia coli, lipopolysaccharides serve as polyclonal B-cell mitogens commonly used in laboratory immunology. (From Dorland, 28th ed)Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.Artificial Gene Fusion: The in vitro fusion of GENES by RECOMBINANT DNA techniques to analyze protein behavior or GENE EXPRESSION REGULATION, or to merge protein functions for specific medical or industrial uses.Agrobacterium tumefaciens: A species of gram-negative, aerobic bacteria isolated from soil and the stems, leafs, and roots of plants. Some biotypes are pathogenic and cause the formation of PLANT TUMORS in a wide variety of higher plants. The species is a major research tool in biotechnology.Guanosine Diphosphate Mannose: A nucleoside diphosphate sugar which can be converted to the deoxy sugar GDPfucose, which provides fucose for lipopolysaccharides of bacterial cell walls. Also acts as mannose donor for glycolipid synthesis.4-Butyrolactone: One of the FURANS with a carbonyl thereby forming a cyclic lactone. It is an endogenous compound made from gamma-aminobutyrate and is the precursor of gamma-hydroxybutyrate. It is also used as a pharmacological agent and solvent.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Rhamnose: A methylpentose whose L- isomer is found naturally in many plant glycosides and some gram-negative bacterial lipopolysaccharides.DNA Transposable Elements: Discrete segments of DNA which can excise and reintegrate to another site in the genome. Most are inactive, i.e., have not been found to exist outside the integrated state. DNA transposable elements include bacterial IS (insertion sequence) elements, Tn elements, the maize controlling elements Ac and Ds, Drosophila P, gypsy, and pogo elements, the human Tigger elements and the Tc and mariner elements which are found throughout the animal kingdom.Soil Microbiology: The presence of bacteria, viruses, and fungi in the soil. This term is not restricted to pathogenic organisms.Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Succinic Acid: A water-soluble, colorless crystal with an acid taste that is used as a chemical intermediate, in medicine, the manufacture of lacquers, and to make perfume esters. It is also used in foods as a sequestrant, buffer, and a neutralizing agent. (Hawley's Condensed Chemical Dictionary, 12th ed, p1099; McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1851)Acyltransferases: Enzymes from the transferase class that catalyze the transfer of acyl groups from donor to acceptor, forming either esters or amides. (From Enzyme Nomenclature 1992) EC 2.3.Conjugation, Genetic: A parasexual process in BACTERIA; ALGAE; FUNGI; and ciliate EUKARYOTA for achieving exchange of chromosome material during fusion of two cells. In bacteria, this is a uni-directional transfer of genetic material; in protozoa it is a bi-directional exchange. In algae and fungi, it is a form of sexual reproduction, with the union of male and female gametes.Sequence Homology, Nucleic Acid: The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.Acyl Carrier Protein: Consists of a polypeptide chain and 4'-phosphopantetheine linked to a serine residue by a phosphodiester bond. Acyl groups are bound as thiol esters to the pantothenyl group. Acyl carrier protein is involved in every step of fatty acid synthesis by the cytoplasmic system.Restriction Mapping: Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.