Gigaspora margarita (GM) belongs to the widespread group of symbiotic fungi, Arbuscular Mycorrhizal Fungi (AMF), which are associated with most plants. This mutualistic relationship plays a crucial role in enhancing plant health and nutrient uptake. Most AMFs confer resistance to plants by stimulating the plant's immune system. Therefore, by providing a natural defense mechanism, they reduce the need for chemical pesticides. Despite some contradictory results, researches have shown that AMF can enhance plant resistance to viral infections. Tomato mosaic virus (ToMV, genus Tobamovirus, family Virgaviridae) is a saptransmissible plant virus that infects tomatoes and other members of the Solanaceae family. It is one of the most common and economically significant viruses that infect tomato plants worldwide. we investigated the effect of GM-tomato interaction against ToMV infection. Several plant morphological and physiological characteristics were evaluated by factorial completely randomized design in three repetitions. All treatments were compared to the plants infected only by ToMV as control. In plants with GM-ToMV treatments, disease severity significantly decreased (-18%). Emergence of viral symptoms also hindered for 6 days. Plant height (+51%) and wet and dry weights of the aboveground plant parts enhanced significantly (+76% and +122%, respectively). GM significantly improved leaf N:P:K content (+400%, +475% and +152% respectively) in ToMV infected plants. Chlorophyll a (+40%) and Chlorophyll b (+75%) significantly increased. Ascorbate peroxidase (+70%) and catalase (+64%) activities and total phenolic content (+126%) significantly improved. The results showed that GM primed tolerance in tomato plants against ToMV and mitigated adverse effects of ToMV infection
