The Function of Arbuscular Mycorrhizal Fungi Associated with Drought Stress Resistance in Native Plants of Arid Desert Ecosystems: A Review

Drought stress profoundly affects native desert plants’ survival and performance. Among all the abiotic stresses, drought is considered a major constraint that influences the structure and functions of desert ecosystems. Arid desert ecosystems are characterized by prolonged drought, extreme temperatures, high solar radiation, water scarcity, high salinity, scarcity of soil nutrients, and poor soil structure. Such extreme desert environments are the toughest regions on earth, which present enormous challenges in conserving plant survival, growth and reproduction. Despite the predominance of these environmental conditions, native desert plant species that grow in desert environments develop complex adaptation strategies and resistance mechanisms to ameliorate the abiotic and biotic stresses in the extreme environments including changes in biochemical, physiological, and morphological levels. Arbuscular mycorrhizal fungi (AMF) form positive symbiotic associations with a considerable percentage of terrestrial plants as their host, induce distinct impacts on plant growth and protect plants from abiotic stresses. However, it is necessary to advance our understanding of the complex mechanisms associated with AMF-mediated and other dark septate endophytes (DSE)-mediated amelioration of native desert plants’ drought stress resistance and associated biological adjustments such as changes in hormone balance, water and nutrient status, stomatal conductance and osmotic adjustment, antioxidant activity, and photosynthetic activity. This review provides an overview of the relationships of mycorrhiza and fungal endophytes involved in drought stress tolerance, summarizing the current knowledge and presenting possible mechanisms mediated by AMF to stimulate drought tolerance associated with native desert plants. We discuss the research required to fill the gaps and provide suggestions for future research.