Query: NC_013859:9500 Azospirillum sp. B510 plasmid pAB510e, complete sequence
Lineage: Azospirillum; Azospirillum; Rhodospirillaceae; Rhodospirillales; Proteobacteria; Bacteria
General Information: Azospirillum are commonly isolated from the rhizosphere and root surfaces from a wide variety of plants. Azospirillum species are considered to be plant growth promoting organisms, producing plant hormones for cell elongation (auxins), cell division and growth (cytokinins) and stem elongation (gibberellins). These compounds contribute to an enhanced uptake of nutrients and water and thus increased plant growth. Azospirillum sp. B510 was isolated from rice in Japan.
Subject: NC_008380:4532969 Rhizobium leguminosarum bv. viciae 3841, complete genome
Lineage: Rhizobium leguminosarum; Rhizobium; Rhizobiaceae; Rhizobiales; Proteobacteria; Bacteria
General Information: This biovar nodulates legumes in the Tribe Viciae (Vicia, Pisum, Lathyrus, Lens). This strain is a spontaneous streptomycin-resistant mutant of strain 300. Nitrogen-fixing plant symbiont. This organism, like other Rhizobia, establishes a symbiotic relationship with a legume plant, providing nitrogen in exchange for a protected environment. The legume roots secrete flavonoids and isoflavonoids which the bacteria recognize and use to turn on genes involved in root nodulation. Many of the root nodulation genes are involved in synthesis and secretion of a nodule inducing signal, a lipochito-oligosaccharide molecule, which the plant recognizes, triggering nodule formation. The bacterium is endocytosed and exists inside a membrane bound organelle, the symbiosome, and fixes nitrogen for the plant cell while the host cell provides carbon compounds for the bacterium to grow on. The nitrogen fixation is important as it obviates the need for expensive and environmentally damaging fertilizer use.