Figure 4.14 The rhizosphere is the narrow zone of soil surrounding plant roots that is characterised by root exudation and an abundance of saprophytic, pathogenic and symbiotic bacteria and fungi. These include rhizobia that form nodules, and arbuscular mycorrhizal fungi (AMF). The rhizoplane describes the root surface in contact with the soil. Root cap and root border cells near the root tip provide lubrication as the root expands into the soil. (Reproduced by permission from Macmillan Publishers Ltd from L. Philippot et al. Nature Rev Microbiol 11: 789-799, 2013)