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.