Exploring the Role of Glomus iranicum in Managing Mild Drought Events in Triticum aestivum cv Peralba

Abstract The use of arbuscular mycorrhizal fungi (AMFs) represents a promising tool for improving the agronomical performance of crops. Our aim was to evaluate the effects of a commercial formulation of Glomus iranicum , also in combination with the biocontrol agent Trichoderma asperellum , on Triticum aestivum in response to mild drought stress. G. iranicum was applied singularly or in association with T. asperellum , as seed coating on wheat, and the effects on seed germination and vigor were evaluated as compared to untreated seeds. The efficacy of microbial treatment was evaluated in a greenhouse experiment on singularly, co-inoculated, and untreated plants in control and mild drought stress condition, on six plants for each experimental condition. Physiological, developmental, metabolic, and molecular parameters were measured. G. iranicum , either alone or in combination with T. asperellum , promoted faster seed germination, while T. asperellum , despite its role as a biofungicide, did not adversely affect the mycorrhization index or seedling development. G. iranicum and T. asperellum , singularly or in combination, determined a significant increase of leaf and root biomass at soil relative water content (SRWC 80%), while in mild stress conditions (SRWC 40%) the sole G. iranicum was effective. Abscisic acid (ABA) content increased in plants treated with G. iranicum , either under water-limiting or control conditions, but the combination with T. asperellum did not attenuate this response. This study demonstrated that G. iranicum and T. asperellum were effective in increasing the resilience of wheat in mild drought stress conditions, potentially increasing the production yield in unfavorable climatic conditions and supporting the development of combined sustainable agronomic practices.