Graphene oxide modification enhances the activity of chitosan against Fusarium graminearum in vitro and in vivo

Fusarium graminearum (F. graminearum), a pathogen for Fusarium head blight (FHB) on wheat, significantly reduces wheat yield and poses potential threats to human food safety. In this study, graphene oxide (GO) modified chitosan (GO-CS composite) was synthesized and its antifungal activity against F. graminearum in vitro and in vivo was evaluated. The 1HNMR and FTIR results revealed the reaction between the carboxyl groups in GO and the amino groups in chitosan (CS). In vitro, the combination of GO and CS resulted in a significant synergistic inhibitory effect on the mycelial growth of F. graminearum relative to single GO or CS. The EC50 value of the GO-CS composite was 14.07 μg/mL, which was much lower than that of GO or CS alone. In vivo, the GO-CS composite significantly reduced the disease incidence and severity compared with single GO or CS, and the control efficacy could reach 60.01 %. Microbial cells might be ultimately damaged when interacting with GO-CS due to various mechanisms such as biological effects and physical barriers. Overall, the combination of GO and CS provides new opportunities for their application in the control of fungi.