 One way this can occur is in the root nodules of legumes that contain symbiotic bacteria of the genera "Rhizobium", "Mesorhizobium", "Sinorhizobium", "Bradyrhizobium", and "Azorhizobium".The roots of plants create a narrow region known as the rhizosphere that supports many microorganisms known as the root microbiome.A lichen is a symbiosis of a macroscopic fungus with photosynthetic microbial algae or cyanobacteria.