Molecular, biological and physiological characterizations of resistance to phenamacril in <i>Fusarium graminearum</i>

Abstract

Fusarium head blight ( FHB ), caused by Fusarium graminearum , is one of the most devastating wheat diseases in China. Phenamacril is a novel cyanoacrylate fungicide with a unique chemical structure and specific mode of action against Fusarium spp. In this study, the molecular, biological and physiological characteristics of laboratory‐induced mutants of F. graminearum with resistance to phenamacril were investigated. Compared to the wildtype strains, the phenamacril‐resistant mutants showed obvious defects in various biological and physiological characteristics, including vegetative growth, carbon source utilization, response to oxidative and osmotic stresses, sensitivity to cell wall and cell membrane integrity inhibitors, cell membrane permeability, glycerol accumulation and pathogenicity. The phenotypes of the phenamacril‐resistant mutants exhibited many variations. Sequencing indicated that the three parental strains studied were identical, and the mutants TXR 1, TXR 2, BMR 1, BMR 2, SYR 1 and SYR 2 each had a single point mutation in the amino acid sequence encoded by the myosin‐5 gene ( FGSG _01410). These results provide new reference information for future investigations concerning the resistance mechanism of F. graminearum to phenamacril and could offer important relevant data for the management of FHB caused by F. graminearum .