2017 ASHS Annual Conference

In this study, evidence for antagonism of antifungal metabolites produced by Bacillus amyloliquefaciens Y1 was established, as they actively inhibited growth of Fusarium graminearum under in vitro and in vivo conditions. The mycelial growth of F. graminearum was strongly inhibited by the culture supernatant and butanol crude extract. In addition, an antifungal compound was purified from the antifungal metabolites of Y1 and identified as cyclo (L- Pro-D-Tyr) using H¹ and C¹³ NMR spectroscopic analyses. For the first time, cyclo (L- Pro-D-Tyr) was shown to have potent antifungal activity against F. graminearum under in vitro conditions. Microscopically, the hyphae of this fungal pathogen became deformed because of the effect of cyclo (L- Pro-D-Tyr). Exposure of F. graminearum to various concentrations of cyclo (L- Pro-D-Tyr) on wheat seeds significantly inhibited its growth and controlled head blight. Furthermore, in an in vivo wheat pot experiment, Y1 resulted in a 27% higher total yield and showed a protective effect against F. graminearum by reducing low discoloration symptoms on stems and the grain yield per pot was five times higher compared to that control pots (Water only) infested with F. graminearum. To our knowledge, this is the first report of the antifungal activity of the cyclo (L- Pro-D-Tyr) against the plant pathogenic fungus F. graminearum. This work also for the first time correlated the plant growth promotion and biocontrol of crown rot in wheat by B. amyloliquefaciens strain. Our results demonstrated the potential of B. amyloliquefaciens Y1 as a biocontrol agent against the head blight and crown rot fungal pathogen as well as a plant growth promoter for wheat.