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Rhizobia
Rhizobia are diazotrophic bacteria that fix nitrogen after becoming established inside the root nodules of legumes (Fabaceae). To express genes for nitrogen fixation, rhizobia require a plant host; they cannot independently fix nitrogen. In general, they are gram negative, motile, non- sporulating rods. Rhizobia are a "group of soil bacteria that infect the roots of legumes to form root nodules". Rhizobia are found in the soil and, after infection, produce nodules in the legume where they fix nitrogen gas (N2) from the atmosphere, turning it into a more readily useful form of nitrogen. From here, the nitrogen is exported from the nodules and used for growth in the legume. Once the legume dies, the nodule breaks down and releases the rhizobia back into the soil, where they can live individually or reinfect a new legume host. History The first known species of rhizobia, '' Rhizobium leguminosarum'', was identified in 1889, and all further species were initially placed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fabaceae
Fabaceae () or Leguminosae,International Code of Nomenclature for algae, fungi, and plants. Article 18.5 states: "The following names, of long usage, are treated as validly published: ....Leguminosae (nom. alt.: Fabaceae; type: Faba Mill. Vicia L.; ... When the Papilionaceae are regarded as a family distinct from the remainder of the Leguminosae, the name Papilionaceae is conserved against Leguminosae." English pronunciations are as follows: , and . commonly known as the legume, pea, or bean family, is a large and agriculturally important family of |
Root Nodules
Root nodules are found on the roots of plants, primarily legumes, that form a symbiosis with nitrogen-fixing bacteria. Under nitrogen-limiting conditions, capable plants form a symbiotic relationship with a host-specific strain of bacteria known as rhizobia. This process has evolved multiple times within the legumes, as well as in other species found within the Rosid clade. Legume crops include beans, peas, and soybeans. Within legume root nodules, nitrogen gas (N2) from the atmosphere is converted into ammonia (NH3), which is then assimilated into amino acids (the building blocks of proteins), nucleotides (the building blocks of DNA and RNA as well as the important energy molecule ATP), and other cellular constituents such as vitamins, flavones, and hormones. Their ability to fix gaseous nitrogen makes legumes an ideal agricultural organism as their requirement for nitrogen fertilizer is reduced. Indeed, high nitrogen content blocks nodule development as there is no benefit for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Root Nodule
Root nodules are found on the roots of plants, primarily legumes, that form a symbiosis with nitrogen-fixing bacteria. Under nitrogen-limiting conditions, capable plants form a symbiotic relationship with a host-specific strain of bacteria known as rhizobia. This process has evolved multiple times within the legumes, as well as in other species found within the Rosid clade. Legume crops include beans, peas, and soybeans. Within legume root nodules, nitrogen gas (N2) from the atmosphere is converted into ammonia (NH3), which is then assimilated into amino acids (the building blocks of proteins), nucleotides (the building blocks of DNA and RNA as well as the important energy molecule ATP), and other cellular constituents such as vitamins, flavones, and hormones. Their ability to fix gaseous nitrogen makes legumes an ideal agricultural organism as their requirement for nitrogen fertilizer is reduced. Indeed, high nitrogen content blocks nodule development as there is no benefit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diazotrophic
Diazotrophs are organisms capable of nitrogen fixation, i.e. converting the relatively inert diatomic nitrogen (N2) in Earth's atmosphere into bioavailable compound forms such as ammonia. Diazotrophs are typically microorganisms such as bacteria and archaea, with examples being rhizobia and ''Frankia'' and ''Azospirillum''. All diazotrophs contain iron-molybdenum or iron-vanadium nitrogenase systems, and two of the most studied systems are those of ''Klebsiella pneumoniae'' and ''Azotobacter vinelandii'' due to their genetic tractability and their fast growth. Etymology The word diazotroph is derived from the words ''diazo'' ("di" = two + "azo" = nitrogen) meaning "dinitrogen (N2)" and ''troph'' meaning "pertaining to food or nourishment", in summary dinitrogen utilizing. The word ''azote'' means nitrogen in French and was named by French chemist and biologist Antoine Lavoisier, who saw it as the part of air which cannot sustain life. Types Diazotrophs are scattered across Bacter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyphomicrobiales
The Hyphomicrobiale' (synonym Rhizobiales) are an order of Gram-negative Alphaproteobacteria. The rhizobia, which fix nitrogen and are symbiotic with plant roots, appear in several different families. The four families '' Nitrobacteraceae'', '' Hyphomicrobiaceae'', '' Phyllobacteriaceae'', and '' Rhizobiaceae'' contain at least several genera of nitrogen-fixing, legume-nodulating, microsymbiotic bacteria. Examples are the genera '' Bradyrhizobium'' and ''Rhizobium''. Species of the '' Methylocystaceae'' are methanotrophs; they use methanol (CH3OH) or methane (CH4) as their sole energy and carbon sources. Other important genera are the human pathogens '' Bartonella'' and ''Brucella'', as well as ''Agrobacterium,'' an important tool in genetic engineering. Taxonomy Accepted families * '' Aestuariivirgaceae'' Li ''et al''. 2019 * '' Afifellaceae'' Hördt ''et al''. 2020 * '' Ahrensiaceae'' Hördt ''et al''. 2020 * '' Alsobacteraceae'' Sun ''et al''. 2018 * '' Amorphaceae'' Hör ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhizobiales
The Hyphomicrobiale' (synonym Rhizobiales) are an order of Gram-negative Alphaproteobacteria. The rhizobia, which fix nitrogen and are symbiotic with plant roots, appear in several different families. The four families '' Nitrobacteraceae'', '' Hyphomicrobiaceae'', '' Phyllobacteriaceae'', and '' Rhizobiaceae'' contain at least several genera of nitrogen-fixing, legume-nodulating, microsymbiotic bacteria. Examples are the genera ''Bradyrhizobium'' and ''Rhizobium''. Species of the '' Methylocystaceae'' are methanotrophs; they use methanol (CH3OH) or methane (CH4) as their sole energy and carbon sources. Other important genera are the human pathogens '' Bartonella'' and ''Brucella'', as well as ''Agrobacterium,'' an important tool in genetic engineering. Taxonomy Accepted families * '' Aestuariivirgaceae'' Li ''et al''. 2019 * '' Afifellaceae'' Hördt ''et al''. 2020 * '' Ahrensiaceae'' Hördt ''et al''. 2020 * '' Alsobacteraceae'' Sun ''et al''. 2018 * '' Amorphaceae'' Hördt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhizobium
''Rhizobium'' is a genus of Gram-negative soil bacteria that fix nitrogen. ''Rhizobium'' species form an endosymbiotic nitrogen-fixing association with roots of (primarily) legumes and other flowering plants. The bacteria colonize plant cells to form root nodules, where they convert atmospheric nitrogen into ammonia using the enzyme nitrogenase. The ammonia is shared with the host plant in the form of organic nitrogenous compounds such as glutamine or ureides. The plant, in turn, provides the bacteria with organic compounds made by photosynthesis. This mutually beneficial relationship is true of all of the rhizobia, of which the genus ''Rhizobium'' is a typical example. ''Rhizobium'' is also capable of solubilizing phosphate. History Martinus Beijerinck was the first to isolate and cultivate a microorganism from the nodules of legumes in 1888. He named it ''Bacillus radicicola'', which is now placed in '' Bergey's Manual of Determinative Bacteriology'' under the gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrobacteraceae
The Nitrobacteraceae are a family of gram-negative, aerobic bacteria. They include plant-associated bacteria such as ''Bradyrhizobium'', a genus of rhizobia associated with some legumes. It also contains animal-associated bacteria such as '' Afipia felis'', formerly thought to cause cat-scratch disease. Others are free-living, such as ''Rhodopseudomonas'', a purple bacterium found in marine water and soils. The strain ''Rhodopseudomonas palustris'' DX-1 can generate an electric current with no hydrogen production, a trait being explored in the development of the microbial fuel cell. The genus ''Afipia'' has also been found in the atmosphere, where it uses methylsulfonylmethane as a carbon source. The bacteria of this family derive their energy from oxidizing ammonia to nitrite, or by oxidizing nitrite to nitrate. They are commonly found in freshwater and soil. Phylogeny The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen Fixation
Nitrogen fixation is a chemical process by which molecular dinitrogen () is converted into ammonia (). It occurs both biologically and abiological nitrogen fixation, abiologically in chemical industry, chemical industries. Biological nitrogen fixation or ''diazotrophy'' is catalyzed by enzymes called nitrogenases. These enzyme complexes are encoded by the Nif gene, ''Nif'' genes (or ''Nif'' homologs) and contain iron, often with a second metal (usually molybdenum, but sometimes vanadium). Some nitrogen-fixing bacteria have symbiotic relationships with plants, especially legumes, mosses and aquatic ferns such as ''Azolla''. Looser non-symbiotic relationships between diazotrophs and plants are often referred to as associative, as seen in nitrogen fixation on rice roots. Nitrogen fixation occurs between some termites and fungus, fungi. It occurs naturally in the air by means of NOx, NOx production by lightning. Fixed nitrogen is essential to life on Earth. Organic compounds such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Host (biology)
In biology and medicine, a host is a larger organism that harbours a smaller organism; whether a parasite, parasitic, a mutualism (biology), mutualistic, or a commensalism, commensalist ''guest'' (symbiont). The guest is typically provided with nourishment and shelter. Examples include animals playing host to parasitic worms (e.g. nematodes), cell (biology), cells harbouring pathogenic (disease-causing) viruses, or a Fabaceae, bean plant hosting mutualistic (helpful) Rhizobia, nitrogen-fixing bacteria. More specifically in botany, a host plant supplies nutrient, food resources to micropredators, which have an evolutionarily stable strategy, evolutionarily stable relationship with their hosts similar to ectoparasitism. The host range is the collection of hosts that an organism can use as a partner. Symbiosis Symbiosis spans a wide variety of possible relationships between organisms, differing in their permanence and their effects on the two parties. If one of the partners in an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soybean
The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean. Soy is a staple crop, the world's most grown legume, and an important animal feed. Soy is a key source of food, useful both for its protein and oil content. Soybean oil is widely used in cooking, as well as in industry. Traditional unfermented food uses of soybeans include edamame, as well as soy milk, from which tofu and tofu skin are made. Fermented soy foods include soy sauce, fermented bean paste, nattō, and tempeh. Fat-free (defatted) soybean meal is a significant and cheap source of protein for animal feeds and many packaged meals. For example, soybean products, such as textured vegetable protein (TVP), are ingredients in many meat and dairy substitutes. Soy based foods are traditionally associated with East Asian cuisines, and still constitute a major part of East Asian diets, but processed soy products are increasingly used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alfalfa
Alfalfa () (''Medicago sativa''), also called lucerne, is a perennial plant, perennial flowering plant in the legume family Fabaceae. It is cultivated as an important forage crop in many countries around the world. It is used for grazing, hay, and silage, as well as a green manure and cover crop. The name alfalfa is used in North America. The name lucerne is more commonly used in the United Kingdom, South Africa, Australia, and New Zealand. The plant superficially resembles clover (a cousin in the same family), especially while young, when glossary of leaf morphology#trifoliate, trifoliate leaves comprising round leaflet (botany), leaflets predominate. Later in maturity, leaflets are elongated. It has raceme, clusters of small purple flowers followed by fruits spiralled in two to three turns containing 10–20 seeds. Alfalfa is native to warmer temperate climates. It has been cultivated as livestock fodder since at least the era of the Ancient Greece, ancient Greeks and Ancient R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
