ABSTRACT
Soil salinity is a major abiotic stress and a main constraint to profitable crop production that adversely affects plant growth (i.e., vulnerability to diseases, physiological disorders, hormonal and nutritional imbalance, ion toxicity, etc.) of more than 20% irrigated land worldwide. Legumes are frequently subject to salinity stress that can intensely influence plant development (i.e., diminished nodulation, N2 fixation, and nitrogenase activity) and threaten legume production worldwide. Thus, improved salinity tolerance in the agriculturally and nutritionally important plants (nodulated legumes), due to their high-grain protein contents and ability to fix biological nitrogen (N2), is absolutely necessary for maintainable crop production on salt–affected soils to ensure future food supplies. Although these plants employ some specific mechanisms such as osmoregulation and osmotic adjustment, hormonal regulation, ion homeostasis, hormonal regulations, and activation of the antioxidant defense system to combat salinity stress, arbuscular mycorrhizal fungi (AMF) have been shown to reduce the intensity of this stress and, as a result, improve the salinity tolerance of legumes used for the food and green manure production in salt–affected soils by various mechanisms. Based on the analyzed documents, provided macronutrients and micronutrients (improvement in soil nutrient cycling of low mobile ions) and improved water supply to stressed plants seem to be the common mechanisms under salinity stress. In this review, the significance of AMF alleviation of salt stress and their beneficial effects on leguminous plant growth and productivity are emphasized.
