Synergistic effects of magnesium nano-oxide and mycorrhizal fungi on metabolite profiles in sesame (Sesamum indicum) under varying water regimes

This study aimed to evaluate the effects of nano magnesium oxide (MgO NPs, OM2) and mycorrhizal fungi species, Funneliformis mosseae (MI2) and Rhizophagus irregularis (MI3), on sesame plants under different environmental conditions. This study was conducted using a factorial field experiment with three replicates over two years (2023–2024) across four environments conditions with varying irrigation levels (optimal and deficit) and rainfall patterns The results showed that OM2 significantly enhanced antioxidant enzyme activities, including superoxide dismutase (SOD) and catalase (CAT), by approximately 29% and 32%, respectively, as well as increased primary metabolites such as soluble sugars (CBD) and proline (PRN). Secondary metabolites like phenolic compounds (PNL) and anthocyanins (ANT) were also elevated, contributing to improved stress tolerance.The mycorrhizal fungi (MI2 and MI3) facilitated nutrient uptake and enhanced root development, particularly under water-limited conditions. In environments with optimal irrigation and high rainfall, the OM2MI2 treatment yielded the highest grain production (1117.52 kg ha-1, a 29% increase over the control), while under water-limited conditions, OM2MI2 achieved 795.76 kg ha-1 (28% higher than the control). The results indicated that OM2 significantly boosted antioxidant enzyme activities (SOD and CAT activities increased by approximately 29% and 32%, respectively, as well as increased primary metabolites such as soluble sugars (CBD) and proline (PRN). Secondary metabolites like phenolic compounds (PNL) and anthocyanins (ANT) were also elevated, contributing to improved stress tolerance The biplot results showed that OM2 and mycorrhizal fungi (MI2) had high yield effects in different environments studied, and had the same position in the two-dimensional principal component diagram. Also, the cluster analysis dendrograms showed that the treatments were grouped together (the group that had the highest yield). Cluster and biplot analyses confirmed that OM2 and mycorrhizal fungi (MI2) effectively enhanced both primary and secondary metabolism, supporting increased stress resistance in sesame plants. This study emphasizes the potential benefits of combining nano magnesium oxide with mycorrhizal fungi to enhance sesame productivity and quality under diverse environmental challenges.