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.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 etli: A species of gram-negative bacteria and nitrogen innoculant of PHASEOLUS VULGARIS.Rhizobium tropici: A species of gram-negative bacteria and an nitrogen inoculum that displays a high intrinsic tolerance to acidity.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.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.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.Rhizobiaceae: A family of gram-negative bacteria which are saprophytes, symbionts, or plant pathogens.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.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.Medicago sativa: A plant species of the family FABACEAE widely cultivated for ANIMAL FEED.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.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)Genes, Bacterial: The functional hereditary units of BACTERIA.Phaseolus: A plant genus in the family FABACEAE which is the source of edible beans and the lectin PHYTOHEMAGGLUTININS.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)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.Bacterial Proteins: Proteins found in any species of bacterium.Mesorhizobium: A genus of gram-negative, rod-shaped bacteria in the family PHYLLOBACTERIACEAE. They are able to invade root-hairs of a wide range of plants, inciting the production of PLANT ROOT NODULES.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.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.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.Medicago: A plant genus of the family FABACEAE. It is distinct from Sweet Clover (MELILOTUS), from Bush Clover (LESPEDEZA), and from Red Clover (TRIFOLIUM).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)Polysaccharides, Bacterial: Polysaccharides found in bacteria and in capsules thereof.RNA, Ribosomal, 16S: Constituent of 30S subunit prokaryotic ribosomes containing 1600 nucleotides and 21 proteins. 16S rRNA is involved in initiation of polypeptide synthesis.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Medicago truncatula: A plant species of the family FABACEAE used to study GENETICS because it is DIPLOID, self fertile, has a small genome, and short generation time.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.Gene Expression Regulation, Bacterial: Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Nitrogenase: An enzyme system that catalyzes the fixing of nitrogen in soil bacteria and blue-green algae (CYANOBACTERIA). EC 22.214.171.124.Leghemoglobin: A hemoglobin-like oxygen-binding hemeprotein present in the nitrogen-fixing root nodules of leguminous plants. The red pigment has a molecular weight approximately 1/4 that of hemoglobin and has been suggested to act as an oxido-reduction catalyst in symbiotic nitrogen fixation.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.Soybeans: An annual legume. The SEEDS of this plant are edible and used to produce a variety of SOY FOODS.Cosmids: Plasmids containing at least one cos (cohesive-end site) of PHAGE LAMBDA. They are used as cloning vehicles.Soil Microbiology: The presence of bacteria, viruses, and fungi in the soil. This term is not restricted to pathogenic organisms.Lespedeza: A plant genus of the family FABACEAE.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.Mutation: 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.Trifolium: A plant genus of the family FABACEAE.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.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.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.Tephrosia: A plant genus of the family FABACEAE that contains tephrorin, tephrosone, and C-prenylflavonoids.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.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Alphaproteobacteria: A class in the phylum PROTEOBACTERIA comprised mostly of two major phenotypes: purple non-sulfur bacteria and aerobic bacteriochlorophyll-containing bacteria.AcetyleneCloning, 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.DNA, Ribosomal: DNA sequences encoding RIBOSOMAL RNA and the segments of DNA separating the individual ribosomal RNA genes, referred to as RIBOSOMAL SPACER DNA.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.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.Rhizobium phaseoli: A species of gram-negative bacteria functioning as a nitrogen inoculum for dry beans, especially species in the genus PHASEOLUS.Acacia: A plant genus of the family FABACEAE. The gums and tanning agents obtained from Acacia are called GUM ARABIC. The common name of catechu is more often used for Areca catechu (ARECA).Mimosa: A plant genus of the family FABACEAE that contains kukulkanin, a CHALCONE.Mutagenesis, 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.Mycorrhizae: Symbiotic combination (dual organism) of the MYCELIUM of FUNGI with the roots of plants (PLANT ROOTS). The roots of almost all higher plants exhibit this mutually beneficial relationship, whereby the fungus supplies water and mineral salts to the plant, and the plant supplies CARBOHYDRATES to the fungus. There are two major types of mycorrhizae: ectomycorrhizae and endomycorrhizae.Cupriavidus: A genus of gram-negative, aerobic, rod-shaped bacteria, in the family BURKHOLDERIACEAE, that are mobile by means of peritrichous FLAGELLA. The genus was formerly called Wautersia and species in this genus were formerly in the genus RALSTONIA.Carbohydrate Sequence: The sequence of carbohydrates within POLYSACCHARIDES; GLYCOPROTEINS; and GLYCOLIPIDS.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.Rickettsiaceae: A family of small, gram-negative organisms, often parasitic in humans and other animals, causing diseases that may be transmitted by invertebrate vectors.Nucleic Acid Hybridization: Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)Glutamate-Ammonia Ligase: An enzyme that catalyzes the conversion of ATP, L-glutamate, and NH3 to ADP, orthophosphate, and L-glutamine. It also acts more slowly on 4-methylene-L-glutamate. (From Enzyme Nomenclature, 1992) EC 126.96.36.199.Cannabaceae: A plant family of the order Urticales, subclass Hamamelidae, class Magnoliopsida. It is most notable for the members, Cannabis and Hops.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Agricultural Inoculants: Beneficial microorganisms (bacteria or fungi) encapsulated in carrier material and applied to the environment for remediation and enhancement of agricultural productivity.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.Lipid A: Lipid A is the biologically active component of lipopolysaccharides. It shows strong endotoxic activity and exhibits immunogenic properties.Restriction Mapping: Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.Melilotus: A plant genus of the family FABACEAE.Dicarboxylic AcidsEscherichia 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.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)DNA, Ribosomal Spacer: The intergenic DNA segments that are between the ribosomal RNA genes (internal transcribed spacers) and between the tandemly repeated units of rDNA (external transcribed spacers and nontranscribed spacers).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.Luteolin: 5,7,3',4'-tetrahydroxy-flavone, one of the FLAVONES.N-Acetylglucosaminyltransferases: Enzymes that catalyze the transfer of N-acetylglucosamine from a nucleoside diphosphate N-acetylglucosamine to an acceptor molecule which is frequently another carbohydrate. EC 2.4.1.-.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.RNA, Bacterial: Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.