Beatrice Buffoni

Agricultural systems are particularly impacted by global climate change (CC), responsible for the introduction of multiple environmental stressors negatively affecting plant growth. Soil microbial communities are crucial in agricultural practices, influencing crop performance and soil health. Human activities and CC threaten soil microbial biodiversity, leading to soil quality degradation and decreasing plant health and productivity. Among plant-beneficial microorganisms, mycorrhizal fungi are widespread in terrestrial ecosystems, including agroecosystems, and they play a key role by enhancing plants’ fitness and resilience to both abiotic and biotic stresses. Therefore, exploring the role of mycorrhizal symbiosis in sustainable agriculture has become increasingly critical. Moreover, the application of mycorrhizal bioinoculants could reduce dependence on inorganic fertilizers, enhance crop yield, and support plants in overcoming environmental stresses. This review, after briefly introducing taxonomy, morphology and mechanisms supporting the symbiosis establishment, reports the roles of mycorrhizal fungi and their associated bacteria in improving plant nutrition and mitigating CC-induced abiotic stresses such as drought and salinity, also giving specific examples. The focus is on arbuscular mycorrhizal fungi (AMF), but ericoid mycorrhizal (ErM) fungi are also considered as promising microorganisms for a sustainable agricultural model. New emerging concepts are illustrated, such as the role of AMF hyphosphere in acting as a preferential niche to host plant growth-promoting bacteria and the potential of ErM fungi to improve plant performance on Ericaceae plants but also on non-host plants, behaving as endophytes. Finally, the potential and limitations of mycorrhizal-based bioinoculants are discussed as possible alternatives to chemical-based products. To this aim, possible ways to overcome problems and limitations to their use are discussed such as proper formulations, the systematic check of AMF propagule viability and the application of suitable agronomical practices in the field.

Durum wheat is one of the most important agricultural crops, currently providing 18% of the daily intake of calories and 20% of daily protein intake for humans. However, being wheat that is cultivated in arid and semiarid areas, its productivity is threatened by drought stress, which is being exacerbated by climate change. Therefore, the identification of drought tolerant wheat genotypes is critical for increasing grain yield and also improving the capability of crops to uptake and assimilate nutrients, which are seriously affected by drought. This work aimed to determine the effect of arbuscular mycorrhizal fungi (AMF) on plant growth under normal and limited water availability in two durum wheat genotypes (Svevo and Etrusco). Furthermore, we investigated how the plant nutritional status responds to drought stress. We found that the response of Svevo and Etrusco to drought stress was differentially affected by AMF. Interestingly, we revealed that AMF positively affected sulfur homeostasis under drought conditions, mainly in the Svevo cultivar. The results provide a valuable indication that the identification of drought tolerant plants cannot ignore their nutrient use efficiency or the impact of other biotic soil components (i.e., AMF).