Arbuscular Mycorrhiza: Physiology of Symbiosis and Application Towards Sustainability

Arbuscular mycorrhizal fungi (AMF) or arbuscular mycorrhizae (AM) that invade the plant roots or reside in the rhizosphere are considered to be advantageous for plant’s development. AM helps the host plants by making favourable alterations in the rhizospheric soil properties and providing vital mineral nutrients, particularly phosphorus. As symbionts with terrestrial plant roots, arbuscular mycorrhizae (AM) are included under the phylum Glomeromycota. The rhizosphere is the place where AM–plant association begins, and it involves a sequence of chemical induction that is released by both the fungus and the plant. Plants commence communication with AM by secretion of chemical induction into the root zone area of plant, in response to deficiency of nutrients like phosphorus and nitrogen, because AM’s major role in the AM–plant association is to give important nutrients. Most AM spores do not necessarily require the chemical cues to germinate. AM spores were thought to be gone through many stages of germination prior to the discovery of chemical signals from a possible host. The fungus actually looks for plant exudates and then branches out in the direction of the exudates it finds. Plants have many mechanisms of tolerance to avoid the harmful consequences of various environmental stresses. One of the most crucial tools is the antioxidant system that involves in tolerance mechanism. Osmolyte formation is aided by AM and also supports the ions’ preferential absorption. Moreover, phosphorus nutrition of host plants is not only boosted by AM rather its development and tolerance potentiality towards drought stress and diseases are also improved. The possibility of regulation of plant growth by using AM has been the subject to numerous research studies. AM can play vital roles in promoting agricultural sustainability, including acting as root symbiont, biofertilizers, enhancing plant water and nutrient absorption, sequestering carbon, making micronutrients more readily available to plants, and improving the surface absorption capacity of host roots. In view of the above, this chapter aims to depict the current state of AM research and its physiology of symbiosis, with a particular focus on AM-induced alterations in plant’s antioxidant and osmolyte metabolisms that support significant adaptations in plants under adverse conditions.