General Information: This strain was isolated from a green alder (Alnus crispa) growing in Tadoussac, Canada. These bacteria were originally linked to fungi, because of the mycelium-like filaments many of them form. This bacterium is able to establish a nitrogen-fixing symbiosis with alder (Alnus spp.) and myrtle (Myrica spp.), two pioneer plant genera of temperate regions, found on forest clearings, mine wastes, sand dunes and glacial moraines where nitrogen is the limiting factor. Frankia alni causes root hair deformation: it penetrates the cortical cells and induces the formation of nodules which resemble those induced by Rhizobium in legumes. These nodules are then colonized by vegetative hyphae (mycelium filaments) which differentiate into diazo-vesicles