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AzorhizobiumRANK: GenusTAXONOMY: cellular organisms -> Bacteria -> Proteobacteria -> Alphaproteobacteria -> Rhizobiales -> Xanthobacteraceae -> Azorhizobium OVERVIEW: Rods 0.5–0.6 × 1.5–2.5 μm. Motile by one polar or subpolar flagellum. Nonsporeforming. Gram negative. Peritrichous flagella are formed on solid media, and a single lateral flagellum is formed in broth. Growth temperature, 12–43°C. Broad optimum pH, 5.5–7.8. Colonies are circular and creamy. Urease negative. Oxidase and catalase positive. Do not denitrify. Of sugars, only glucose is oxidized. The organic acids lactic acid and succinic acid are preferred substrates for growth, both under and not under nitrogen-fixing conditions. Growth on malonate and dl-proline. Starch is not hydrolyzed. Nitrogen-fixing root- and stem-nodulating microsymbiont of Sesbania rostrata. Readily fixes nitrogen ex planta under microaerobic conditions and with nicotinic acid provided. Can grow on nitrogen-free medium, unlike all other legume microsymbionts, of the genera Bradyrhizobium, Rhizobium, and Mesorhizobium, which lie in distinct families.The mol% G + C of the DNA is: 66–68.Type species: Azorhizobium caulinodans |