Pre_GI: SWBIT SVG BLASTN

Query: NC_016582:6448430 Streptomyces bingchenggensis BCW-1 chromosome, complete genome

Lineage: Streptomyces bingchenggensis; Streptomyces; Streptomycetaceae; Actinomycetales; Actinobacteria; Bacteria

General Information: Streptomyces bingchenggensis BCW-1 was isolated from a soil sample collected in Harbin, China. This species produces milbemycins, a family of macrocyclic lactones widely used in human health, animal health, and crop protection. The characteristic earthy smell of freshly plowed soil is actually attributed to the aromatic terpenoid geosmin produced by species of Streptomyces. There are currently 364 known species of this genus, many of which are the most important industrial producers of antibiotics and other secondary metabolites of antibacterial, antifungal, antiviral, and antitumor nature, as well as immunosuppressants, antihypercholesterolemics, etc. Streptomycetes are crucial in the soil environment because their diverse metabolism allows them to degrade the insoluble remains of other organisms, including recalcitrant compounds such as lignocelluloses and chitin. Streptomycetes produce both substrate and aerial mycelium. The latter shows characteristic modes of branching, and in the course of the streptomycete complex life cycle, these hyphae are partly transformed into chains of spores, which are often called conidia or arthrospores. An important feature in Streptomyces is the presence of type-I peptidoglycan in the cell walls that contains characteristic interpeptide glycine bridges. Another remarkable trait of streptomycetes is that they contain very large (~8 million base pairs which is about twice the size of most bacterial genomes) linear chromosomes with distinct telomeres. These rearrangements consist of the deletion of several hundred kilobases, often associated with the amplification of an adjacent sequence, and lead to metabolic diversity within the Streptomyces group. Sequencing of several strains of Streptomyces is aimed partly on understanding the mechanisms involved in these diversification processes.

Subject: NC_012850:4422966 Rhizobium leguminosarum bv. trifolii WSM1325, complete genome

Lineage: Rhizobium leguminosarum; Rhizobium; Rhizobiaceae; Rhizobiales; Proteobacteria; Bacteria

General Information: Temp: Mesophile; Habitat: Host, Root nodule. This biovar is a symbiont of clover plants and is important commercially as it is used in the agricultural industry. Strain WSM1325 is compatible with many perennial clovers of Mediterranean origin used in farming, such as T. pratense, and is therefore one of the most important clover inoculants but is incompatible with American and African perennial clovers, such as those nodulated by the dissimilar strain WSM2304. 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.