The effects of arbuscular micorizal fungus (AMF) and strigolactone treatments against foot and root rot disease (fusarium culmorum (W.G. Smith) Saccardo) in wheat

Wheat, a crucial agricultural crop globally, faces significant threats from fungal pathogens, particularly Fusarium culmorum (FC), which causes foot and root rot (FRR), as well as Fusarium head blight (FHB). This study investigates the effects of rac-GR24, a synthetic analogue of Strigolactone (SL), and arbuscular mycorrhizal fungi (Funneliformis mosseae, AMF) on plant growth, physiological responses, development of resistance to the disease at the molecular level and soil health in wheat plants against FRR caused by FC. The research utilized FC-sensitive 'Esperia' and resistant 'Demir 2000' wheat varieties. In the preliminary phase, the optimal SL concentrations (0, 1, 5, 10, 15, and 20 μM) and application methods (rhizosphere and foliar) were assessed to identify the synergistic effects with AMF. Analyses of 72 parameters, including plant morphology, chlorophyll content, phosphorus levels, and mycorrhizal symbiosis, indicated that a concentration of 15 μM applied through the rhizosphere was the most effective. The main experiment further detailed the impact of AMF and SL treatments on plant growth and defense mechanisms in both FC-sensitive and resistant wheat varieties. The synergistic effects of SL and AMF resulted in significant improvements in parameters such as plant morphology, chlorophyll content, biochemical activities and phosphorus uptake, which favoured plant health and growth. Especially in the sensitive variety Esperia, a balanced increase in total phenolic content, antioxidant activity and proline levels was achieved and the defence capacity against disease stress was strengthened. Molecular analyses revealed that the co-treatment of AMF and SL significantly influenced the expression of plant development genes (Rubisco, TEF) and defense-related genes (PAL, PR2, PR3, PR4). The expression of PAL and PR3/PR4 genes was upregulated, while PR2 gene expression was downregulated, enabling the plant to enhance its disease resistance through a targeted defense strategy. Regarding soil health, AMF and SL treatments elevated enzyme activities (catalase, urease, dehydrogenase) and increased glomalin production, which in turn fortified the microbial community and improved organic matter cycling. These findings underscore the potential of SL and AMF treatments to diminish the reliance on chemical fertilizers and pesticides, promoting sustainable agricultural practices.