Arbuscular Mycorrhizal Fungi: The Natural Biotechnological Tools for Sustainable Crop Production Under Saline Soils in the Modern Era of Climate Change

Degradation of land and deterioration of the environment are two major problems in agriculture. Scientists recently warned that 24 billion tons of fertile soils are being lost in every year, largely due to unsustainable agriculture practices. It is estimated that about 25% of the total global land area has been degraded resulting in substantial economic impacts on agricultural livelihoods and national economies, especially in the lower-income countries. If this trend continues, 95% of the Earth’s land area will be degraded by 2050. Soil salinity is considered as the most important abiotic stress, which is responsible for land degradation particularly in arid and semi-arid regions, leading to cause a major challenge to sustainable agriculture. To deal with saline soils and minimize crop loss, new salt-tolerant crop plants developed through classical breeding and genetic engineering have been considered. Besides, several lines of evidence indicate that arbuscular mycorrhizal fungi (AMF) promote plant growth and enhance salinity tolerance by employing various mechanisms including enhanced nutrient acquisition by AMF-colonized plant roots. This chapter covers the occurrence of AMF in saline soils and effect of salinity on the AMF colonization, hyphal length and sporulation both in vivo and in vitro. It also covers literature relating to the alleviation of salt stress by AMF and its beneficial effects on growth and modulation of biochemical, physiological and molecular mechanisms in the host plants to tolerate salt stress. The chapter also overviewed areas where more investigations are required to gain a thorough understanding of the different mechanisms AMF symbiosis to protects plants from salt stress.