Plasma-activated water for inactivation of Fusarium graminearum spores: An in-vitro wheat study

Fusarium graminearum (F. graminearum) as the major pathogen for Fusarium head blight (FHB) in wheat can cause severe yield loss and secrete mycotoxins to contaminate grain. Herein, this study prepared a novel green fungicide named plasma-activated water (PAW) by only using air, water and electricity via cold plasma activation, and investigated its antifungal effects against F. graminearum spores. The in-vitro results showed that PAW achieved a 1.98 to 3.98 log reduction of F. graminearum spores for treatment times ranging from 30 to 120 min. PAW also efficiently inhibited mycelial growth, spore germination and fungal pathogenicity of F. graminearum. Hydroxyl radicals and hydrogen peroxide were identified as the major antifungal agents in PAW, which destroyed the intracellular redox homeostasis and cell membrane of F. graminearum, eventually causing cell necrosis. PAW maintained a strong antifungal activity (4 log reduction) at a maximum dilution ratio of 6:4 and storage time of 2 h. The field-plot experiments verified that PAW effectively controlled wheat FHB via decreasing the disease incidence, FHB index, deoxynivalenol contamination and weight loss of wheat grains. The results demonstrated that PAW holds a great potential as an efficient, economical, and green fungicide for FHB control in wheats.