Query: 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.
Subject: NC_002932:2142000 Chlorobium tepidum TLS, complete genome
Lineage: Chlorobaculum tepidum; Chlorobaculum; Chlorobiaceae; Chlorobiales; Chlorobi; Bacteria
General Information: This green-sulfur bacterium is a thermophile and was isolated from a New Zealand high-sulfide hot spring. Photosynthetic thermophile. Chlorobium tepidum is a member of the green-sulfur bacteria. It has been suggested that the green-sulfur bacteria were among the first photosynthetic organisms since they are anaerobically photosynthetic and may have arisen early in the Earth's history when there was a limited amount of oxygen present. This organism utilizes a novel photosynthetic system, and harvests light energy using an unusual organelle, the chlorosome, which contains an aggregate of light-harvesting centers surrounded by a protein-stabilized galactolipid monolayer that lies at the inner surface of the cytoplasmic membrane. Unlike many other photosynthetic organisms, the green-sulfur bacteria do not produce oxygen and tolerate only low levels of the molecule. This organism also fixes carbon dioxide via a reverse tricarboxylic acid cycle, using electrons derived from hydrogen or reduced sulfur to drive the reaction, instead of via the Calvin cycle like many other photosynthetic organisms.