Microbial solutions to mitigate salt stress in food crops

In the next decades, the demand for food will dramatically increase driven by the expected rise of world human population. However, climate change and associated abiotic stresses are declining global agriculture production, especially in arid and semiarid areas, which experience high evapotranspiration rates and low availability of water, leading to the salinization. Agricultural sustainable management practices to attain healthy soils are now required due to international directives and to a shift to a green agriculture that needs to thrive. This encourage the use of mitigation strategies for salinized areas, which include soil and water management practices and the utilization of salt-tolerant crops by farmers, the latter not being a guarantee of success, as reported by several authors. The harnessing of soil beneficial microorganisms including plant-growth promoting bacteria (PGPB) and arbuscular mycorrhizal fungi (AMF) to enhance crops' capacity to thrive in salt-affected areas has been gaining ground in the last decade, constituting an eco-friendly alternative to conventional mitigation salt stress strategies. Bio-amelioration of salt stress in plants is often associated to a plethora of nutritional, biochemical, and physiological processes that act together for improving crop resilience and yield under saline conditions. These mechanisms include higher water use efficiency and absorption of nutrients, maintenance of ionic homeostasis, higher accumulation of osmoprotectants, and enhanced photosynthetic efficiency and antioxidant system.