Root Silicon Amendment Enhances Barley’s Resistance to Fusarium Head Blight in the Field

Abstract

Background: Silicon (Si) amendment plays an important role in enhancing the resistance of several plant species to diverse pathogens. To date, a few studies have focused on how Si application helps barley, a higher Si absorber and accumulator monocot, to resist fungal diseases, including Fusarium head blight (FHB), which reduces the quality and safety of harvested products worldwide. However, no study has ever been conducted to demonstrate Si's ability to suppress FHB development in barley heads under uncontrolled climatic conditions. Materials and Methods: This 2-year field study elucidated the effect of multiple Si applications at 1.7 mM via roots in two barley cultivars, Arabi Aswad (AS moderately resistant) and Arabi Abiad (AB moderately susceptible), to control four Fusarium species with diverse pathogenicity. The incidence of FHB (DI type I resistance), severity of FHB (DS type II), and Fusarium-damaged kernels (FDK type III) were also tested to describe the nature of the Si-enhanced barley resistance. Results: Si treatment at 1.7 mM under soil culture decreased FHB development by enhancing all resistance types measured in the present research. DI, DS, and FDK were reduced by 18.7%, 20.3%, and 20.2%, respectively, in Si-Fusarium-inoculated treatments relative to fungal-inoculated controls. Si absorption in barley strengthened the defense system measured by type I and type II on AB to a level comparable to AS not amended with Si. Irrespective of the barley cultivar, however, Si resulted in a quasi-similar reduction of FDK. Importantly, Si treatment at 1.7 mM decreased the damage of FHB in previous analyses conducted on AS and AB under in vitro and growth chamber environments, showing that Si enhanced the expression of resistance to FHB infection in seedlings and adult barley plants. Conclusion: All of these results are promising outcomes for the application of Si as a safe and effective method against Fusarium species. This study provides new insights into the potential of multiple Si applications at 1.7 mM via roots for boosting barley’s resistance to FHB with a bright prospect for Si use in barley cultivation under field conditions.