Mycorrhizal Allies in a Warming World: Reducing Fusarium Wilt in Tomato Under Simulated Heat and Water Stress

ABSTRACT Fusarium wilt, caused by Fusarium oxysporum f. sp. lycopersici (Fol), poses a major threat to tomato ( Solanum lycopersicum ) production, particularly under heat and drought stress associated with climate change. This study investigated the potential of a commercial mycorrhizal formulation to protect tomato plants from Fol and enhance resilience under combined biotic and abiotic stresses. Tomato plants were grown under controlled conditions of two temperatures (25°C and 30°C) and two soil moisture levels (100% and 70% field capacity [FC]), with or without Fol inoculation and mycorrhizal treatment. Plant growth, disease progression and fungal biomass in roots were assessed. Results demonstrated that Fol strongly suppressed plant growth, particularly under elevated temperature and drought stress. Mycorrhizal application consistently reduced disease severity and Fol biomass across all treatments, with the most pronounced protective effects observed under heat and drier conditions. Importantly, shoot fresh weight was improved in Fol‐inoculated plants treated with the mycorrhizal formulation, indicating enhanced plant performance despite pathogen pressure. These findings highlight the potential of mycorrhizal application as a promising strategy for shielding tomato plants against Fol, particularly under combined biotic and abiotic stress. The observed benefits align with principles of sustainable agriculture, offering an environmentally friendly and effective alternative for disease management in the context of a changing climate. Integration of mycorrhizae into tomato cultivation systems holds significant promise for fostering crop resilience, enhancing plant health and supporting sustainable, climate‐adapted agricultural practices.